Technical knowledge of raising chickens

Chickens are the most common poultry raised by human beings. Domestic chickens come from wild raw chickens, which have been domesticated for at least 4000 years, but it was not until around 1800 that chicken and eggs became mass-produced commodities. The kinds of chickens are turkey, black chicken, pheasant and so on.

Establish a correct concept of culture

1. Set up the consciousness of improved varieties.

Some farmers' choice of chicks, first of all, is that the price is cheap, and whether the chicks are good breeds is limited to the appearance of the chicks. It is wrong to evaluate the chicks through their external characteristics such as their cry, mental state, black belly and big belly. Although these are the most basic standards, it is often the connotation of chicks that determines chicken production performance-whether the species, age, hatching time, individual size and maternal antibodies of chicks purchased are consistent, especially with the expansion of breeding scale, this connotative factor will become more and more important, and it will directly affect the growth uniformity and immune effect of chickens in the future. The production performance and some indicators of laying hens will also be affected.

2. Brooding and breeding are equally important.

The high and stable yield of chicken flocks is the guarantee to obtain the maximum benefit, and the cultivation of qualified reserve chickens is an important link of high and stable yield. Most farmers tend to focus on the brooding stage, and in the main period of determining high yield-the early stage of breeding (whether the body weight of 10-week-old chickens reaches the standard or not will determine about 80% of the laying performance of laying hens). Because it can not bring obvious economic benefits, it is often ignored by farmers, many farmers at this stage, in order to save feeding costs, use low-quality formula feed As a result, the body weight of 8-10 weeks old was not up to standard, the uniformity of the flock was poor, and the main management period to determine its high yield was missed, which led to the adverse effects of low egg laying performance, low egg laying peak and short duration of egg laying peak.

3. Attach importance to peacetime management

Some farmers think that after the chicken has been vaccinated, everything will be free from all diseases and everything will be fine. Often do not pay attention to immunization procedures and feeding management, such as free-range chickens can be seen everywhere, sick and dead chickens are thrown everywhere in river ditches, roadsides, front and back houses, artificially causing the recurrence and prevalence of many infectious and parasitic diseases, causing great economic losses to the chicken industry. Vaccinate chickens, the immunization procedure is very important.

① in the formulation of immunization procedures, according to the local area, the actual situation of the breeding community, reference to the immune procedures provided by the brooding company, vaccine varieties, the time to produce protective power and other factors.

② should choose high-quality vaccine and grasp the injection site and dose.

It is best not to use live vaccination against viral infectious diseases that do not occur locally in ③.

After each vaccination, ④ should carefully disinfect the empty bottles, vaccination utensils, nasal drops, eye drops and injection places.

4. Strengthen disinfection

Disinfection is the only means to kill bacteria and viruses in chicken sheds and sports places, and it is one of the important measures to keep the environment clean and healthy. One of the important reasons for the high morbidity and mortality of chickens is that disinfection has not been done or not done thoroughly, poor environmental hygiene, and the existence of pathogenic microorganisms; in some breeding areas, farmers are relatively casual in each other's houses, and there are no necessary disinfection troughs, disinfection pots and basic disinfection measures at the door of the chicken house, let alone cross-disinfection. Artificially increased the incidence of conditional pathogens-Escherichia coli and mycoplasma disease in farmers. Farmers must enhance the awareness of disinfection and disease prevention, seriously, carefully, and attach great importance to disinfection work.

5. Pay attention to feed quality and use less medicine.

Feed is the basis of the production performance of chickens, high-quality, comprehensive and reasonable feed can often give full play to the maximum production potential of chickens, make chickens high and stable yield, and produce higher economic benefits.

In the actual breeding process, because the feed cost accounts for about 75-80% of the breeding cost, some farmers only pay attention to the feed cost and do not pay attention to the feed quality. In fact, the use of poor quality feed, the input-output ratio is higher than good quality; in low-quality feed often contains a large number of miscellaneous meal, in which anti-nutritional factors and some pathogenic factors will greatly reduce the level of nutrition available in the feed, but also lead to body disorder, easy to be infected with the virus, thus increasing the mortality of chickens, resulting in a great impact on production.

According to the growth of chickens and the need for disease prevention in a certain period, it is appropriate to add some drugs to the feed in the short term. However, the phenomenon of drug abuse in some farmers is very serious, mixed with drugs in feed all the year round, which not only causes drug waste, but also easy to produce drug resistance, once they get sick, it is very difficult to treat. Poisoning caused by long-term drug use is also common. Therefore, the disease of chickens should be diagnosed in time, prescribe the right medicine to the case, and absolutely not use medicine at will, blindly, or increase the dosage. It is even more forbidden to use drugs as health care agents and growth-promoting agents for a long time. If drugs must be used, attention should be paid to: the selection and compatibility of drugs should be reasonable, the dosage should be accurate, and the time of drug use should be appropriate. General drugs should not be used continuously for more than a week to avoid drug resistance and adverse reactions. Planned use of drugs to prevent the occurrence of epidemic diseases, according to the incidence of the field, planned administration of drugs to chickens at a certain age, can be achieved in advance of prevention, prevent or reduce the occurrence of epidemic diseases.

Chicken farms must attach great importance to feed and drinking water sanitation. Fish meal and bone meal often contain salmonella and E. coli, which should not be used to feed chickens. Quality inspection should be carried out every time the feed is fed, and it is found that the seriously polluted feed should not be fed to chickens. In order to prevent the spread of diseases through feed, the feed can be heated by steam (80 ℃ for 3 minutes) and made into pellet to feed chickens. Chicken drinking water should be clean and free of pathogens. In order to prevent waterborne diseases, disinfection drugs such as sodium hypochlorite and permethrin can be added to drinking water, feeding management should be strengthened and scientific feeding methods should be adopted to reduce the occurrence of chicken diseases.

6. Strategies and measures to reduce the incidence of chicken disease.

All entry and exit of ① is the basic condition to control the epidemic disease: the scientific method of raising chickens is to raise adult chickens separately from adult chickens and chicks, and the hatchery must be far away from the chicken farm. It is absolutely forbidden to keep chickens of different ages in a chicken house so that all chickens go in and out. That is, when you enter the chicken, fill the henhouse at once, and after all the chickens are out of the pen, the whole house will be thoroughly cleaned, cleaned and disinfected. The empty house will be empty for 2 to 4 weeks, and then enter the new chicken.

② to achieve isolation breeding: to prevent the occurrence of infectious diseases, a very important one is isolation breeding, to prevent pathogens from spreading to the field. This requires chicken farms to be built on high terrain, flat and open, convenient for drainage, good water quality and far away from villages and towns, factories and meat packing plants. The chicken farm is not allowed to be visited by outsiders. People entering the farm should take a bath, change their clothes and change their shoes to prevent outside poultry from entering the farm. Do not buy feed from epidemic areas, do not use moldy and deteriorated feed. Pay attention to the prevention of birds, rats, mosquitoes and flies, etc. The resistance of chicks is very weak and is easy to be infected with diseases. In order to ensure the safety of chicks, it is best to keep the breeders in the henhouse during brooding.

7. Pay attention to the environmental hygiene of chicken farms.

The environment of the chicken house includes the small environment of the chicken flock (chicken house) and the large environment (production area). In a chicken farm with good environmental hygiene, chickens are relatively healthy and rarely get sick, and once an epidemic occurs, it is also easy to control.

The environment of the chicken house includes the temperature, humidity, wind speed, dust, harmful gases and pathogenic microorganisms in the chicken house. These conditional indexes have a great impact on the growth and development and disease resistance of chickens. All measures should be taken to create a good environment for chickens and ensure the health of chickens.

Regular disinfection of chickens in the henhouse can reduce the content of dust and pathogenic microorganisms in the air of the henhouse, which is of great significance to ensure the health of the flock. Disinfection of chickens in summer can also cool down. If the content of ammonia in the chicken house exceeds 20ppm, it will affect the growth, development and disease resistance of chickens, and induce respiratory diseases such as infectious rhinitis and mycoplasma disease. Attention should be paid to solving the contradiction between heat preservation and ventilation in autumn and winter. There should be a clean channel and a dirty channel in the chicken farm, which is a channel for transporting feed and products (eggs, chickens), etc., and a channel for transporting chicken droppings, dead chickens and garbage.

There can be no chicken droppings and feathers in the field. Clean and disinfect regularly, at least once a week, and dig the ground deeply if necessary. Dead chickens should not be thrown about. They should be collected in time, boiled, burned or buried deep.

The chicken droppings cleared from the chicken coop should be transported in time and can be fermented or dried. The wastewater discharged from the chicken house should be treated innocuously.

8. Strengthen feeding and management

First of all, it is necessary to meet the nutrients needed for chicken growth, development, egg laying or meat growth, such as protein, carbohydrates, fats, minerals and vitamins. Different chicken breeds have different requirements for each nutrient in different growth stages and different seasons, which should be adjusted according to the actual situation. Trace element selenium and vitamin E play an important role in chicken immunity, so it is necessary to ensure supply.

When the conditions of beak amputation, herding, immunity or feeding of chickens change greatly, stress reaction will occur, and the demand for vitamin A, vitamin K and vitamin C should be supplemented in time.

Feeding and management of laying hens in spring

The temperature outside the house gradually increases in spring and the natural sunshine time is gradually prolonged, which is not only a more suitable period for laying eggs, but also the key to brooding in one year. But at this time, a variety of pathogenic microorganisms also began to reproduce, the climate is changeable, and the temperature difference between day and night is large. In this way, the following problems need to be done well in different stages of feeding and management.

1. Feeding and management of chicks in the stage.

① spring chicks: that is, the chicks hatched from March to April every year are spring chicks. During this period, the climate is gradually getting warmer, which is very beneficial to the growth of chicks, and the survival rate of brooding is high. The new chicken began to be laid from August to September of that year, which was the declining season of the old chicken laying last year, which could make up for the shortage of fresh egg supply in the off-season market, and the egg production could not be molted until the end of the second autumn, so the economic benefit was higher.

② late spring chicks: the chickens hatched from late April to May every year are late spring chicks. At this time, the climate is warmer, the management is convenient, the cost of heat preservation is reduced, and the survival rate of brooding is higher. The new chicken starts production at the end of autumn and the beginning of winter, and the peak is before the Spring Festival. The price of eggs is higher, which can achieve better economic benefits.

③ temperature: the temperature of the chick in the first week was 35 ℃ 36 ℃, and then decreased by 2 ℃ per week. Because the egg yolk is not absorbed well after coming out of the shell, the physique is weak and the resistance is poor, the use of high temperature brooding can promote the absorption of egg yolk and reduce mortality.

④ humidity: due to the high temperature during the breeding period, low humidity in the house, easy to dry, causing dust, and extremely easy to cause foreign body tracheitis, therefore, we should regularly increase humidity, chicken spray disinfection, can also put an iron basin on the stove, regularly put chlorine disinfectant, to achieve disinfection and increase humidity two purposes. The general humidity of brooding is 65%.

⑤ beak breaking: the purpose of beak breaking is to prevent and cure pecking, usually at the age of 6-10 days for the first time, and at the age of 14-10 weeks for the second time. Use a special tool to cut off the upper beak and lower beak, and cut off the upper beak and lower beak. If you cut off too much, it will affect feeding and growth, cut off too little, and peck when laying eggs.

⑥ ventilation: 1 the heat preservation is main for 2 weeks, but don't forget ventilation, the ventilation volume should be increased in the third week; in the later stage, with the acceleration of chicken growth, chickens need relatively more oxygen, so ventilation is particularly important at this stage. While keeping warm in spring, regular ventilation should be carried out to reduce the concentration of harmful gases such as dust, carbon dioxide and ammonia in the house, reduce the humidity in the house and keep the air fresh, so as to achieve the purpose of reducing the occurrence of respiratory and intestinal diseases.

⑦ disease prevention: the diseases easy to occur during the breeding period are chicken pullorum, omphalitis, enteritis, bursal disease, coccidiosis and so on. Drugs should be given regularly to prevent the disease and do a good job of epidemic prevention. Develop immunization procedures according to local conditions.

2. Back-up chicken feeding and management

① to cultivate healthy and high-quality backup laying hens: select breeds and disease purification of good breeding farms to buy young chickens. In the early stage of brooding, the temperature in the house should be kept at 32-20 ℃, and a 40-watt bulb should be used to increase the brightness of aerial lighting to provide sufficient slots for full feeding; in the middle and later stages, ventilation should be paid attention to, and feeding should be restricted according to the growth and development of chickens, so as to prevent excessive fat accumulation from affecting egg production in the later stage. Do a good job in disease prevention and immunization, especially for infectious diseases such as Newcastle disease, Marek's disease, infectious bursa and infectious bronchitis, we should focus on immunization, improve uniformity, and cultivate qualified reserve layers.

② strict epidemic prevention system: establish a sound epidemic prevention system, and unremittingly implement it. Establish a full-in-all-out system, carefully clean and wash the henhouse before entering the chicken, thoroughly disinfect it; after entering the chicken, remove the feces and bedding materials in time and dispose of them properly. Disinfect chickens 2 or 3 times a week, set up disinfection plates at the door of the henhouse for trampling in and out, sprinkle disinfectant frequently every day, change into epidemic prevention clothes when entering the house, and strictly prohibit idle people from entering. Kill rodents regularly to prevent birds from entering through the window and stop the spread of disease. The sick and dead chickens should be buried or burned in time. Clean the door of the chicken house and the surrounding environment on time, and spray disinfectant at the same time.

③ adjust feed ratio: in spring, the proportion of nutrients in feed must be adjusted in order to achieve better feeding benefit after the laying hens enter the peak laying period.

④ adequate clean drinking water: ensure that chickens drink enough and clean water to avoid water outage, especially in high temperature weather, lack of drinking water for a long time is bound to lead to a decline in egg production, and the mortality rate will increase when heat stress intensifies. Those who drink with a sink or drinking fountain should be cleaned every day to remove waste and other dirt, and then put in clean water; nipple drinkers should always check the dripping condition and repair it in time when it is found that there is no water coming out.

⑤ control the light: after the backup layer is caged, the light time should be increased slowly. Due to the difference of varieties, the increasing speed of light time is also different, it is generally appropriate to increase by half an hour a week, and it will be constant after 16 hours of sunlight at the age of 27 weeks. Some chicken farmers have a small body weight when they start production because of poor feeding conditions or improper management. at this time, on the basis of strengthening feeding management, the light time can be increased by 15 minutes per week, so that the weight of starting production is consistent with sexual maturity. If the light is not enough due to power outage and other reasons, candlelight and other measures should be taken to supplement the lighting.

⑥ proper ventilation: the air environment has a direct impact on the health and production performance of chickens. In addition to dehumidification and dust removal, ventilation also plays a role in improving air conditions and temperature control. The temperature changes greatly in spring, and many farmers are used to closing doors and windows. Ventilation can reduce the harmful gases in the house, so that the concentration of ammonia is less than 20 × 10-6, the concentration of hydrogen sulfide is less than 10 × 10-6, and the allowable concentration of carbon dioxide is not more than 0.5%. It should be noted that night ventilation must not be ignored.

⑦ suitable temperature and relative humidity: too high or too low temperature in the house will affect the activity, diet and physiological metabolism of chickens, and then affect egg laying performance and feed efficiency. When the temperature is low, we should pay attention to prevent cold and keep warm; provide diets with appropriate levels of nutrition. In the actual production, the temperature in the house should be controlled at 10-27 ℃ as far as possible. Relative humidity has little effect on chicken flock, but it may also cause serious harm when other factors act together. For example, high temperature and high humidity or low temperature and high humidity may lead to chicken disease, the former is easy to make pathogenic microorganisms survive for a long time, chicken heat dissipation is blocked, the latter is easy to make chicken body cool, feed consumption is too low, the same relative humidity is too low, can aggravate the chance of airborne diseases, prone to respiratory and other infectious diseases. Generally speaking, it is better to prevent moisture and keep the chicken coop drier.

⑧ control weight: due to the rapid growth of chicken bones in the first 10 weeks, the skeleton of 8-week-old chicks can be 75% complete and more than 90% complete at 12 weeks, then grow slowly, and the bone development is basically completed at 20 weeks old. The development of body weight reached 75% at the age of 20 weeks, and then developed slowly, until the growth stopped at the age of 36 mi 40 weeks. The main way to control body weight is to restrict feeding: in order to avoid chickens with shank length up to standard and underweight, chickens whose shin length is not up to standard and overweight, chickens should be properly restricted during the breeding period. Starting at the age of 8 weeks, there are two methods: limited quantity and limited quality. The limited quantity method is often used in production, because this can ensure that the intake of chicken is the nutritional balance of diet. The limit method requires that the feed quality is good and must be full-price feed, and the daily feed intake of chickens should be reduced to about 80% of the free feed intake, and the specific feeding amount should be determined according to the chicken breeds and flock conditions.

3. Feeding and management of laying hens before laying.

A few weeks before the beginning of laying is the transitional stage of the hen from the growing period to the laying period. At this stage, not only a series of work such as herding, selection and elimination, immunization, feed replacement and increasing light should be carried out, which will cause great stress to the chickens, but also during this period, the hens have severe physiological changes, sensitivity, weak adaptability and poor disease resistance. If the feeding management is improper. It is easy to affect the performance of laying eggs.

① transferred to the cage: it is most suitable to be caged before 100 days of age, so that the new hens have a period of time to familiarize themselves with and adapt to the environment, and have sufficient time for vaccination, beak trimming, grouping and other work. If caged too late, the opening time of laying will be delayed and the laying rate will be increased; hens that have already started will stop production due to strong stress such as herding, and even some chickens will cause yolk peritonitis and increase the rate of death. If it is premature, it will affect growth.

② vaccination: before the start of production, all the vaccines should be vaccinated, influenza inactivated vaccine should be vaccinated twice, about 30 days apart; laryngotracheitis vaccine had better wipe the anus.

③ deworming: to do a good job of deworming before the start of production, 110 Mel 130-day-old chickens were fed with levamisole 20 Mel 40 mg per kg body weight, once a day for 2 days, and 100,200 mg thiobichlorophenol per kg body weight, once a day for 2 days to dispel tapeworm.

④ increases light: chickens whose body weight meets the requirements or is slightly larger than the standard weight can increase the light hours to 13 hours at the age of 17 weeks, and then increase by 30 minutes a week until the hours reach 16 hours, while low-weight chickens should begin to light stimulation when laying eggs at the age of 130 days. Light hours should be gradually increased, if the sudden increase of light time is too long, it is easy to cause prolapse of the anus; light intensity should be appropriate, not too strong or too weak, too strong easy to produce pecking, too weak will not play a stimulating role. For the new hens bred in the open henhouse, the breeding period is affected by natural light, and the light intensity is strong, and the light intensity should be kept within the range of 15 murals and 20 lux before and after laying, otherwise the light effect is poor.

⑤ change feed: the calcium deposition ability in the bone is the strongest 2 weeks before laying. In order to make the hen high yield, reduce the egg breakage rate, and reduce the occurrence of fatigue of laying hens, the feed should be changed into pre-laying feed (containing 2% calcium) or peak laying feed (3.5% calcium content) in time when increasing light.

4. Feeding and management of laying hens during laying period.

The optimum temperature of laying period for laying hens is 13 ℃ 23 ℃. When the temperature is lower than 5 ℃, the egg production decreases obviously and the feed consumption increases. Therefore, in the spring with changeable climate, in order to maintain stable and high production, it is necessary to carry out scientific feeding and management.

① heat preservation and ventilation: although the temperature outside the house rises gradually in spring, the climate is changeable and the temperature difference between morning and evening is large. The daily feed intake and drinking water of laying hens are more, and the air is easy to be polluted, which affects the health of laying hens and reduces the laying rate. Therefore, attention must be paid to ventilation to make the air in the house fresh. At the same time of ventilation, we should also pay attention to heat preservation. The number, size and direction of opening windows should be determined according to the temperature, wind force and wind direction. Open the upper window first, then the lower window, open the window during the day, close at night, open the window when the temperature is high, close when the temperature is low, open the window when there is no wind, and close when it is windy. This can not only avoid the occurrence of chicken respiratory disease in spring, but also improve the laying rate.

② light management: short days and long nights in spring, natural light is insufficient, artificial light must be supplemented to create light to meet the physiological needs of laying hens. The method is to hang a 25-watt bulb with a lampshade (calculated as 3 watts per square meter) about 2 meters above the ground, and the distance between the lamp and the lamp is about 3 meters. If there are multiple rows of light bulbs, they should be staggered so that the ground can be illuminated evenly and the utilization rate of electric lamps can be improved. It is necessary to adopt the method of combining supplementary light in the morning and evening, and the time of making up light is relatively fixed to prevent the front and back, more and more and less. It is necessary to keep the total light time of laying hens for 15 murals for 16 hours.

③ provides adequate nutrition: for peak laying hens, when the laying rate is more than 85%, the daily protein intake should be 18 grams, and the metabolic energy should be 1.26 megajoules, so the metabolic energy per kilogram of feed should be 11.56 MJ, crude protein 17% MJ 18%, calcium 3.6% Fue 3.8%, phosphorus 0.6%. In order to ensure the energy required for laying hens, the wheat bran in the feed should be less than 5%. 2% grease can be added from February to March.

④ added preventive drugs: as the egg laying peak of new hens comes quickly and lasts for a long time, preventive drugs should be added at different stages to prevent salpingitis, diarrhea, respiratory tract and other diseases. For example, the treatment of 4000 chickens raised by a chicken farmer in Jinan was neglected during the peak period due to long-term chronic diarrhea, resulting in atrophy of the chicken crown and decline in egg production.

5. feeding and management in the later stage of egg production.

In the later stage, the body weight of laying hens almost did not increase, the egg production decreased gradually, and the quality of eggshell gradually became worse. Therefore, feed nutrition should be adjusted in time and management should be strengthened.

① calcium supplement: in order to make chickens produce as many high-quality eggs as possible, reasonable calcium supply is particularly important. A normal eggshell contains about 3 grams of calcium, but the retention rate of calcium in the body is only 50 per cent, so it takes 4 grams of calcium to lay an egg, which is in great demand. If the lack of calcium will promote eating, so that excessive feed consumption, hen weight gain, resulting in increased fat deposition in the liver, resulting in fatty liver. If the calcium in the feed is too saturated, it will reduce the chicken's appetite and affect the laying rate. If there is a serious lack of calcium in the feed, the eggshell will become worse, the soft-shell eggs and shellless eggs will increase, and even paralyze the hens, resulting in fatigue of caged chickens. In the later stage, the content of calcium in the feed was 3.6% at 62 weeks old and 3.8% at 63 weeks old. Shell, stone powder and calcium hydrogen phosphate are good sources of calcium, but they should be matched properly. Some stone powders contain low calcium and some calcium hydrogen phosphate is high. Attention should be paid to fluorosis. If the whole stone powder is used, it will affect the palatability of the chicken, and then affect the appetite. In practice, when the shell powder is added with 2pm 3 and the stone powder is added with 1pm 3, not only the eggshell strength is the best, but also it is economical and practical. Most hens form eggshells at night and lay eggs the next morning. Hens feel calcium deficiency during the formation of eggshells at night. If sufficient calcium is supplied in the afternoon to allow hens to eat freely, they can adjust their feed intake by themselves. The amount of calcium consumed during eggshell formation is 92% of that under normal conditions, while it is only 86% during non-eggshell formation. Therefore, 4-5pm is the prime time to supplement calcium, for every 100 chickens with poor eggshell quality, add 500 grams of shell powder or stone powder every day, so that the chickens are free to use.

② timely elimination of diseased chickens, low-production chickens and low-production chickens: observe the flocks carefully at ordinary times, and timely eliminate the chickens with no feeding value according to their appearance and physiological status; after the egg production peak is over, after the egg production rate is reduced to 80%, strengthen the elimination of off-laying chickens, low-production chickens and diseased chickens, and improve feed utilization.

Prevention and treatment of common chicken diseases

1. Atypical Newcastle disease

The occurrence of ① atypical Newcastle disease: in terms of the characteristics of the disease, typical ND is rare, while atypical ND is more common; the occurrence of local epidemic is less, but more sporadic; less occurs in multiple chicken houses, more in one or individual flocks, or more in batches of chickens at a certain age.

Diagnosis and prevention of ② atypical ND: before autopsy, we should know in detail the number, age, feeding mode, management and post-morbidity of the flock, such as the mental state of the flock, the change of feed intake, the number of diseased chickens, the speed of transmission and clinical symptoms, etc., as well as the immunity before the disease. It includes the type of vaccine, the method of immunization, the time of the last immunization and the interval between the last immunization and the previous immunization, antibody surveillance and IBD immunization. During the autopsy of sick and dead chickens, the focus of observation was on the changes of intestinal tract, in which the diagnostic changes were duodenal mucosa, lymphoid accumulation behind yolk pedicel, ileocecal lymphoid accumulation, cecal tonsil and cloacal mucosa. Often, we can not see all the changes in one chicken, so we should compare the changes of several chickens. At the same time, we should also note that other diseases often secondary to ND, such as colibacillosis, often cause misdiagnosis and bring unnecessary losses to production.

In addition to strengthening comprehensive veterinary health and epidemic prevention measures, the strict implementation of scientific immunization procedures is crucial. A scientific immunization procedure should be based on the actual antibody surveillance in this field, combined with the vaccine. In the event of an epidemic, the effect of emergency immunization varies from region to region. It is suggested that the effective traditional Chinese medicine preparation and immune enhancement drugs should be used.

2. Avian influenza

The epidemic characteristics of ① avian influenza: it can occur in all seasons, but it occurs more frequently in spring and autumn and less in summer; the incubation period varies greatly according to the number of infected viruses, virulence, species of infected birds, environmental conditions and infection routes; poor feeding and management conditions are important inducements; clinical symptoms are different in different species and groups. The performance of different species, groups and batches of the same subtype of virus infection is also different; there are many complications and secondary diseases; the mortality is very different.

Clinical and pathological features of ② avian influenza: low pathogenic avian influenza chickens showed less serious respiratory symptoms, some dyspnea and individual dysentery. The population showed an increase in body temperature, a decrease in appetite, a hindrance to growth and development, and a significant decrease in egg laying rate. Highly pathogenic avian influenza often breaks out suddenly and often dies in large numbers without showing any symptoms. In a short time, you can see loss of appetite, sudden rise in body temperature, high depression of spirit, swelling of head and neck, and difficulty breathing. Low pathogenic avian influenza showed congestion in the tracheal ring, exudation in the trachea, needle-sized bleeding spots on heart fat, catarrhal enteritis in some cases, egg atrophy in adult hens, tubal congestion and massive inflammatory exudation. Highly pathogenic avian influenza is characterized by hemorrhage and swelling in various tissues and organs of the whole body.

③ chicken kidney type infectious bronchitis: chicken kidney type transmission mainly occurred in the brooding stage, the most frequently occurred at the age of 15-40 days, there were more batches of chickens in large farms, and the age of onset was quite stable in a certain period of time. The disease can spread rapidly in the same flock of chickens, the incubation period is very short, generally within ten to dozens of hours. The disease often occurs in late autumn and early spring, and the diseased chickens begin to show transient respiratory symptoms, with slight dyspnea and cough, which are often ignored, followed by increased thirst of chickens, more than two times the amount of drinking water than normal, reduced food intake, depressed spirit, loose bowels, and a 2-3 times increase in defecation. Then there are a large number of deaths, with 40% or more deaths in severe flocks. The kidney of the dead chicken showed obvious changes, such as extreme swelling, lighter color, mottled surface, dilated ureter due to urate deposition, and gouty stone formed by urate deposition in some cases.

At present, H120 and H52 vaccines are mainly used in the prevention of chicken IB in China, but these two vaccines have almost no protective effect on chicken kidney type IB. In order to effectively control chicken kidney type IB, the vaccine containing kidney type IB serotype (W93) must be used on the premise of basic immunization of H120 and H52.

In addition, chronic respiratory disease (CRD) caused by mycoplasma gallisepticum (MG) and infectious rhinitis caused by multiple factors are also very serious in spring, especially the mixed infection of these pathogens and Escherichia coli makes clinical treatment more difficult. But as long as the detection is early and the diagnosis is accurate, sensitivity should be used.

3. Chicken ascariasis

It is mainly parasitic on the small intestine of chickens and is round nematode. The flocks of 3 ~ 4 months old are most likely to be infected, especially when the protein and vitamin feed is insufficient.

The symptoms are loss of appetite, emaciation and weakness, upside-down feathers and drooping wings. The egg production of adult chickens decreased and the eggshell became thinner. Prevention is mainly to strengthen feeding management, pay attention to environmental disinfection and drinking water sanitation.

[treatment] 15 grams of ① bamboo leaves and 15 grams of pepper, stir-fried and ground yellow powder, each chicken was fed with 0.02g mixture twice a day for 3 days. ② tobacco powder: the tobacco powder is rubbed into powder and mixed in the feed, the dosage is about 2% of the feed amount, continuously fed for 7 days, after an interval of 1 month, and then fed for 7 days. Insect repellent, no insect can play a role in preventing the occurrence of ascariasis. Soaking tobacco for chickens to drink as water also has an effect. ③ sulfurized diphenylamine: the deworming effect is very good, and the toxicity is low, and it is safe. 0.5 grams per kilogram of body weight for chicks and 1 gram per kilogram of body weight for adult chickens. Can be mixed in the feed, fed in the evening feeding, take for two days, every other week with the same dose for another two days, basically can dispel the insects clean. ④ albendazole: 30 mg per kilogram of body weight, can be directly taken or mixed into the feed for chickens to eat by themselves.

4. Taeniasis

Chickens are infected by feeding on cysticercus-like cysticerci in intermediate hosts such as flies and earthworms.

[symptoms] diarrhea, feces often with blood and tapeworm body segments, dissection of the small intestine has nodules or inflammation, the intestines are full of white banded worms, the clinical symptoms of diseased chickens are like squatting on the railing, shrinking head standing, frequent drinking, emaciation and weakness.

[treatment] 10 grams of ① pomegranate bark, 15 grams of neem bark, 2-3 grams each time, mixed and fed for 3 times in the morning. ② is mixed with sulfur dichlorophenol powder, according to 100mg/kg body weight, while drinking water with compound vitamin B to promote digestion.

5. Chicken coccidiosis

Most of them occurred in 15-45-day-old chickens.

[symptoms] diarrhea, hematochezia, growth stagnation, mental retardation, stagnation, often emaciation and death, with a mortality rate of more than 50%.

[prevention and treatment] ① should strengthen feeding management, pay attention to environmental hygiene and disinfection, and the breeding density of chickens should not be too high. ② garlic 50g mashed, add 100ml of water, mix feed, once a day, continuous feeding for 5 days. ③ Portulaca oleracea and iron amaranth are 150g each, chopped and mixed for self-eating, once a day for 5-7 days. ④ drug treatment, dysentery, Dianjing, anti-ball king and so on are all effective.

6. Chicken tissue trichomoniasis (also known as blackhead disease)

The disease often occurs in the warm and hot season from late spring to early autumn. The disease is caused by tissue trichomonas drilling into the cecal wall to propagate, entering the bloodstream and parasitic on the liver. Chickens from 2 weeks to 4 months of age are susceptible, with an incubation period of 7 to 12 days, and adult chickens will also occur, but show recessive infection and become carriers. Poor management conditions, damp henhouse, overcrowding, poor ventilation, insufficient light, poor feed quality, inadequate nutrition and so on can be the inducement of the disease, and promote the prevalence of the disease and aggravate the disease.

[symptoms] in the early stage, diseased chickens showed loss of appetite, loose feathers, drooping wings, lethargy, fear of cold extrusion, emaciation, anemia, dysentery, yellowish or light green feces, containing blood, and excreted a large amount of blood in severe cases. The skin of some diseased chickens is bruised and blue-purple, which is known as blackhead disease.

[treatment] ① dysentery. 0.04% was added to the feed, that is, 4 tablets (0.1 g per tablet) were added to the feed for 5 to 7 days. ② metronidazole (metronidazole). Mix the feed with 400 mg / kg for 5 days. ③ levamisole. When the sick chicken turned to recovery, it was used to dispel the heterothorn nematode, 25 mg (1 tablet) per kilogram of body weight. Injections are also available. 5% of the injection is commonly used, and 0.5 milliliters of drugs are injected into muscles per kilogram of body weight. This kind of respiratory tract infection is easier to control.

7. Big head and fat face syndrome

[symptoms] swelling around the diseased corns, head and face, and even jaw and flesh droop, showing a typical "big head fat face" shape, and showing certain neurological symptoms such as head shaking and torticollis. Subcutaneous examination of the head and face showed yellow jelly-like or purulent edema. The disease is a multi-factor infectious disease caused by avian pneumonia virus and secondary bacterial infection such as pathogenic Escherichia coli.

[prevention and treatment] ① improves the feeding environment. ② can be treated with sulfamethoxine (0.03%), ciprofloxacin or ampicillin to prevent secondary bacterial infection, and can be appropriately combined with antiviral drugs. ③ was injected with attenuated vaccine (1-day-old spray) or inactivated vaccine.

8. Fatty liver syndrome

[symptom] the disease is a nutritional disease caused by the disturbance of fat metabolism in chickens. Suffering from chicken crown and beard pale anemia, gray white sparse feces, head and neck protruding or back bending, falling spasm, and finally emaciated to death.

[prevention and treatment] ① controls the energy level in the diet and increases the protein content by 1% and 2%. ② was supplemented with 100g choline chloride, 50g methionine, 5g multivitamin, 12mg vitamin (B12) and 0.05Mel 0.1mg selenium every 100kg feed. ③ diseased chickens were fed with choline chloride 0.1 Mel 0.2 g and vitamin E1 mg respectively. At the same time, 30 grams of Bupleurum, 20 grams of Scutellaria baicalensis, Salvia miltiorrhiza and Rhizoma Alismatis, 10 grams of Schisandra chinensis, 10 grams of Schisandra chinensis, 10 grams of Schisandra chinensis, 20 grams of Radix Bupleuri, 20 grams of Radix Scutellariae, 20 grams of Radix Salviae Miltiorrhizae, 20 grams of Radix Scutellariae, 20 grams of Radix Salviae Miltiorrhizae, 20 grams of Radix Scutellariae and 10 grams of Schisandra chinensis.

9. Abdominal distension syndrome

[symptoms] 4Mel 5-week-old chickens are prone to this disease: abdominal enlargement, head and face purplish, dyspnea, gradual failure and death. Autopsy examination of dead chickens showed that the abdomen was filled with yellowish fluid, pericardial effusion, right heart dilatation, pulmonary congestion, edema, liver and gastrointestinal atrophy, congestion. The disease is caused by chronic hypoxia, cold, high concentration of ammonia and lack of selenium, vitamin C, phosphorus and genetic factors.

[prevention and treatment] ① prevents the administration of sulfonamides and furans which are toxic to kidney and liver, and aminoglycosides, quinolones and other antibiotics should not be used too much. ② this disease often secondary to colibacillosis or chronic respiratory disease, you can choose ampicillin or amoxicillin (10g / 100kg water), ciprofloxacin (5m / 10g / 100kg water) antibiotics to prevent secondary infection. ③ is supplemented with 500g selenium auxin and appropriate amount of vitamin E in every 100kg feed.

10. Bad habits and addiction syndrome

[symptoms] insufficient nutrition or improper proportion of various nutrients in the diet, coupled with poor environment and poor management, there are a large number of bad habits in chickens, such as anus pecking, feather pecking, toe pecking, egg pecking and mutual pecking of chicken body.

[prevention and treatment] the beak of ① was cut off for the first time at the age of 5-9 days, and the beak was trimmed for the second time at the age of 12 weeks. ② preparation of full-price diet, reasonable feeding, scientific management. ③ maintained a suitable feeding density. ④ added 1% Mel 2% gypsum powder and 1% Mel 2% salt to the diseased chicken diet. ⑤ found that sick chickens were isolated in time, and the wound could be smeared with iodine tincture, purple potion, camphor oil, etc., to prevent festering.