TODAY'S SCIENCE TRIVIA: Spontaneous sex reversals in chickens are extremely rare, but they are possible. Scientists aren't 100% sure why they even happen in the first place, but evidence points to changes in sex steroid hormone action.
Typically, a hen's right ovary and oviduct regress during embryonic development. This leaves the chicken with only one functioning ovary, the left one. However, if the left ovary is removed or becomes dysfunctional for any reason, the right ovary's medullary tissue will change into an ovotestis and secrete androgens, which will then result in lowered estrogen levels and the "masculinization" of the hen
