Cock crowing is controlled by internal biological clock, but external light and sound stimulation can also induce rooster crowing, but the influence of external stimulation on rooster crowing is also controlled by internal biological clock of rooster.

When the cycle of light and darkness is changed, the rooster shows the jet lag phenomenon like people flying across large time zones. This is because the biological clock of chicken, like that of human, is influenced by melatonin secreted at night (in the dark). At the same time, cock crowing is also related to chicken androgen. Capons and hens can't crow precisely because they don't have androgen. If they are injected with androgen, hens will also start crowing.

Except for a few birds, such as owl and Siniperca chuatsi (a kind of bird of prey similar to owl, whose difference is that owl has two feathers like cat ears on its head, but Siniperca chuatsi doesn't), other birds can't see at night. Roosters are the same. At night, they may be attacked at any time, so they feel very uneasy.

In the morning, the rooster's eyes can see again, so he is extremely excited. In order to express this excitement, I started to sing excitedly. This is also an instinctive reaction of the rooster to light stimulation. After a long time, crowing in the morning has become a habit of roosters. Even if the rooster is put in a dark place so that it can't see the light, it will still crow in the early 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 rooster also crows to attract the attention of the hen to remind her that there is a handsome man here, but don't go anywhere else. In a word, cock crows have many different meanings, so the way of crowing is also very different.