Cocks and poultry have many varieties, short wings and can't fly high. Crows can announce the dawn. The rooster is the national bird of France, because it is brave, tenacious, aggressive and hardworking. Rooster is a good painting subject, because it is physically strong, brightly colored and agile, which is closely related to people's lives.

Hens can ovulate every 25 hours or so, and only the left ovary and fallopian tube develop. After fertilized eggs are discharged from hens, if the critical hatching degree (24℃) is not reached, they will stop developing.

The reproductive system of rooster consists of testis, epididymis, vas deferens and mating apparatus. What artificial insemination personnel need to know most is the structure of rooster mating organs.

A rooster doesn't have a penis like a mammal, but it has a mating organ consisting of nipple, glandular duct, penis and lymphatic folds. The copulatory organ is located on the ventral side of cloaca, and it is always hidden in cloaca. During sexual excitement, the lymphatic vessels in the glandular duct, penis and lymphatic folds communicate with each other, and the lymphatic folds erect, and lymph flows into the penis to make it swell.

A deep longitudinal groove is formed at the midline, and the middle penis body (central white body) at the front end of the midline also protrudes forward because of the inflow of lymph. At this time, the whole penis is pushed out from the anus and abdomen and inserted into the hen's anus.