How do chicks distinguish between male and female? What are the key technical points of identification?

Chicken farmers all know that after the chicks come out of the shell, the sex identification of the newborn chicks and the timely elimination or fattening of the male chicks can improve the flock uniformity and feed reward, and have obvious economic benefits. So how do chicks distinguish between male and female? What are the key technical points of identification?

I. anal reversal or mold touch identification

1. Male chicks

Near the second and third folds of the inferior wall of the cloacal cavity near the anal opening, there is a spherical process the size of sesame seeds, surrounded by regular folds on both sides, showing a figure of eight, also known as "eight-shaped folds". The globular process is called "reproductive process". The protuberant and zigzag folds are white and slightly glossy. Elastic. Full, not easy to deform when under pressure and friction, toughness, obvious outline

2. Female chicks

Under normal circumstances, the reproductive eminence of newborn female chicks is almost completely degenerated, which is called normal type, but a small number of female chicks are not completely degraded. It can be judged according to the following points.

(1) appearance feeling: the outline of reproductive eminence of female chicks is not obvious, atrophy, the surrounding tissue is weak, there is a sense of isolation.

(2) luster: the reproductive eminence of female chicks is soft and transparent.

(3) elasticity: the elasticity of reproductive eminence of female chicks is poor, and it is easy to deform by compression or extension.

(4) degree of hyperemia: the blood vessels of reproductive eminence of female chicks are underdeveloped, and it is not easy to stimulate hyperemia, while the blood vessels of reproductive eminence of male chicks are well developed; there are small blood vessels and hyperemia on the surface.

(5) the shape of the front end of the protuberance: the front end of the reproductive eminence of the female chicks is sharp, while that of the male chicks is round.

3. Anal identification method

(1) grasping and grasping chicks: there are two commonly used grip methods and group grip methods. The grip method is commonly used. This method is taken as an example below.

(2) defecate and turn the anus: before turning the anus, the feces are excreted first, and the left thumb gently presses the lower edge of the left hip bone of the abdomen to squeeze the feces into the defecation tank with the help of chicken breathing. Thumb pressure must be moderate. if you use light force, the feces should not be drained. If you work hard, you will seriously injure the chicks, or even squeeze out the unabsorbed yolk, resulting in death.

(3) turning the anus: hold the chick with the left hand, the left thumb to the left side of the anus, the left index finger bent and attached to the back of the chicken, and the right index finger to the right side of the anus. Right thumb to the umbilical cord of the chicken. Push the right thumb upward and pull the right index finger down in a straight line, pull it to the anus and fold the left thumb in. then the three fingers close together to form a triangular area, the three fingers close together and squeeze, and the anus opens.

(4) Identification: it can be judged according to the existence and morphological difference of reproductive eminence. If there is a water sample or feces affecting vision, you can quickly wipe it gently with the left thumb, and then observe with the naked eye. If the reproductive bulge is temporarily difficult to distinguish, you can touch it with the left thumb to observe its elasticity and hyperemia. Combine the above differences between male and female to distinguish carefully.

(5) release chicks: light and fast are required when releasing chicks.

In general, the method has a misjudgment of 1.4-1.8%, and is easy to cause harm to chicks and lead to a mortality rate of 0.5-1.0%. As a result, the method is considered to be the most complex method of male and female identification, requiring specialized technicians, heavy workload and extremely boring.

2. Identification of sex-related traits

Based on the principle of sex-linked inheritance, the commercial newborn chicks produced by crossing with specific breeds or strains have obvious differences in feather color, feather shape or skin, so as to accurately identify male and female.

This method is accurate and convenient, and is widely used in modern chicken industry. There are mainly two kinds of methods:

The main results are as follows: (1) Silver feather color is dominant to golden feather white and golden yellow is recessive. Mating with a silver-white rooster and a golden hen, the offspring have a silver-white rooster and a golden hen.

(2) slow-growing feather to fast-growing feather (slow feather) means that the main wing feather is as long as the main wing feather or the main wing feather is longer than the main wing feather, and the fast-growing type (fast feather) means that the main wing feather is longer than the main wing feather. Promoting feathering is dominant and fast feathering is recessive. The slow feathering hen is mated with the fast feathering rooster. In the offspring, the fast feathering type is the hen and the slow feathering type is the rooster.