Common causes of stress in chickens

In production, especially in intensive production, chickens have a certain adaptability and adaptability to the stimulation of feeding density, climate, immunization, transfer, grouping, capture, beak breaking, light and other factors. If the intensity of these stimuli is too strong or lasts too long, which exceeds the physiological tolerance of the body, it will affect the growth, development, reproduction and disease resistance of chickens. And even cause death directly. The main factors that cause chicken stress are as follows.

First, physiological stress. The high-yield chickens raised on a large scale are all caged or kept in cage. if the absolute amount of feed is insufficient or nutrients are not balanced, adrenocortical hormone deficiency will occur and cause stress. When chicks are in a state of stress, they require a lot of vitamins, more than twice the normal amount.

In the non-stress period, in order to make rational use of feed, broilers need to be rich in vitamin C, the normal chicken body can synthesize part of vitamin C, but in the stress period, due to the decrease of synthetic ability, it is easy to reduce the storage of vitamin C in the adrenal gland.

Second, environmental stress. The living environment of chickens includes temperature, light, gas, noise and so on.

1. Temperature: under normal circumstances, the growth rate and egg production of chickens can play their best when the temperature is 18-23 ℃ and the relative humidity is 60-70%. If the meteorological conditions change sharply, such as the summer temperature is more than 30 ℃, the winter temperature is lower than 5 ℃, and the daily temperature difference is more than 10 ℃, the growth and development of broilers will be affected. When the ambient temperature reached more than 30 ℃, in addition to stress reactions, heat stress reactions such as decreased spermatogenesis in cocks, delayed sexual maturation in hens, decreased fertilization rate, decreased blood calcium content, blood acid-base imbalance, and high mortality could be caused in severe cases. Cold also causes chickens to pile up, and weak chicks are often crushed and crushed to death.

2. Light: unreasonable light or sudden changes in light time and light intensity can cause strong stress in the production of chickens, especially laying hens, resulting in a significant decrease in egg laying rate.

3. Gas: a large amount of ammonia is easy to be produced in the case of high density of chickens, poor ventilation and damp accumulation of chicken manure. The long-term survival of chickens in the environment with high ammonia concentration will not only slow down the growth rate of broilers and decrease the egg production of laying hens, but also damage the cardiovascular system and cause respiratory disease infection and ascites.

4. Noise: if the sound exceeds the World Health Organization standard of 45 decibels, or abnormal sounds, sudden sounds and other recurrent noises are very sensitive to chickens. Such as firecrackers, airplanes, cars, trains and other noise can make chickens have a stress response, resulting in loss of appetite and egg production, and even death.

Third, management stress. The stress caused by mistakes in feeding and management is the most common and influential stress in chicken production.

1. Drinking water and feed: sudden changes and deficiencies in the quality of drinking water and feed, such as restricting water supply, even if it is only 1-2 days, light will stagnate the growth and weight gain of chicks within 7-14 days. If the water limit lasts longer, it can cause a significant decline in productivity, even death. Therefore, it is very important for chickens to drink high-quality drinking water. When the feed quality suddenly changes or has a peculiar smell, it can also significantly affect the feed intake of chickens.

2. Feeding density: reasonable feeding density is very important in the process of raising broilers. Many farmers worry that low density can easily lead to waste of chicken sheds, but for fast-growing broilers, reasonable feeding density can make the flock achieve high evenness. When the feeding density exceeds the standard of reasonable feeding density, the more serious the stress is, the greater the effect on chicken productivity is. At the same time, high feeding density can also infect diseases due to stress, such as staphylococcosis, chest, leg, claw trauma, dysplasia and anal pecking.

3. Capturing and breaking beak: beak breaking and capture is a strong stress for chickens, which can affect the utilization of feed and weight gain. In order to reduce the stress of beak breaking, the operation of beak breaking should be skillful and fast, and should be carried out as early as possible. It is not advisable for some people to carry out vaccination and beak cutting at the same time in order to reduce a stress, because it increases the degree of stress.

4. Chicken transportation: the transportation, movement and long-distance transportation of chicks will consume the physical strength and water of chickens, which is a kind of serious stress. The transportation time should be shortened as much as possible, adequate drinking water should be given after arrival, and antibiotics and vitamin additives should be added to the feed.

5. Vaccination: although vaccination is an indispensable part of epidemic prevention measures, no matter which way it is, it is a kind of stress. The process of vaccine entering the body to produce immunity is also a kind of stress. If chicks are infected with mycoplasmosis and Newcastle disease is immunized with aerosol, it can cause chronic respiratory disease.

Fourth, disease and drug stress. Chronic or recessive infection of some bacteria, viruses or internal and external parasitic diseases becomes chronic or subclinical asymptomatic infection because of the relative balance between the body and these pathogens. If other diseases are infected at this time, or the climate, feeding and management conditions deteriorate, it can show serious clinical symptoms and cause huge losses.

Excessive administration of some drugs, such as sulfonamides, some antibiotics, dysentery, quinolinol and other drugs, excessive or long-term use of drugs, serious poisoning, light affect the synthesis of intestinal vitamins, resulting in subcutaneous bleeding and other stress symptoms. Improper selection and use of some disinfectants can also cause stress.