It is a well-documented fact that female chickens (hens) can take on the characteristics and behaviour of male chickens and essentially turn into cockerels.
How is this possible?
Female chickens only have one functioning ovary, although they are born with two. The right ovary becomes dormant in every hen (it is not defined as an ovary or testes and is a non-functioning sex organ), the left ovary is responsible for egg production.
In some circumstances, where a health-related issue such as an ovarian cyst or adrenal gland disease is present, the left ovary shrinks. As the hen ends up without a left ovary, the dormant right sex organ starts to grow but may take the form of a male testes.
The resulting “he / she” will develop the large comb and wattles of a cockerel and may start to crow. However, she will not be a fully functioning cockerel, nor will she lay eggs.