Hens can't crow originally, but when their physiological gonads change, they will crow like cocks.
Do people have such a saying?
People think this phenomenon is unlucky.
Knowledge expansion:
1. Every chicken has testicles and ovaries. The left ovary of hen is developed and the right gonad is underdeveloped. Under the influence of external stimuli and other reasons, gonads may develop. If the gonads develop, the hen's feathers and cockscomb will change and crow. It is precisely because there is a well-developed ovary on the left side of the hen's body that the ovary can not only lay eggs, but also be an endocrine organ, which can produce some estrogen chemicals (called estrone) to maintain its femininity. If the left ovary shrinks for some reason or surgery, and the undeveloped gonad on the right develops into testis instead of ovary, the hen will crow at this time.
Generally speaking, when a hen crows, it will be killed. Some places will hang its chicken head on a tree to burn incense and pray. I think this phenomenon is a bad omen. See (Romance of the Three Kingdoms? "The first time was in February of Jianning four years, the Luoyang earthquake; The sea overflowed and the coastal residents were swept into the sea by the big waves. In the first year of Guanghe, the hen became male. On the first day of June, it was more than ten feet dark and flew into Xiong Wenting.