The cock crows and the hen lays eggs, which is a common thing.
It turned out that except for a few birds such as owl and Swan (a kind of Raptor similar to owl, the difference is that the owl has two feathers like cat ears on its head, while the Swan doesn't), other birds can't see at night. Roosters are the same. They are likely to be attacked at any time at night, so they feel very uneasy. In the early morning, the cock's eyes could see things again, so he was very excited. In order to express this excitement, he began to sing excitedly. This is also an instinctive response of cocks to light stimulation.
After a long time, morning crowing has become a habit of cocks and has been preserved. Now, even if the rooster is placed in a dark place so that it can't see the light, it will still crow in the morning. In addition, the rooster is also a very aggressive animal. It warns other roosters not to come to its territory by crowing, otherwise it will be impolite. The cock also calls to attract the hen's attention to remind the hen that there is a beautiful man, but don't go anywhere else.
In short, cock crowing has many different meanings, so the way of crowing is also very different. If students often listen, they can find the mystery.
Hens laying eggs is just a physiological phenomenon It has nothing to do with mating
The principle of laying eggs by hens: the ovaries on one side of the hen degenerate and the ovaries on the other side produce mature eggs that enter the fallopian tube through the bell mouth at the front end of the fallopian tube. The fertilization process occurs at the upper end of the fallopian tube (the eggs we eat are not fertilized). During the descending process of the fallopian tube, the fertilized eggs are successively wrapped by the protein secreted by the wall of the egg delivery tube, the shell membrane and the egg shell. When the eggs move in the fallopian tube, they rotate due to the movement of the wall muscles and are wrapped with a protein layer, The protein at both ends forms a lace with torsion, which is the white ribbon at both ends of the egg yolk we found when we opened the raw egg.
The eggshell is 89% ~ 97% calcium carbonate, with a small amount of salts and organic matter. Some eggs have colors and patterns, which are produced by pigment cells in the lower tube wall of the fallopian tube