Can a chicken change its gender?
Due to an ovarian change that affects the balance of hormones in
chickens and other birds, it is very rarely possible for a female
bird to adopt male secondary sex characteristics (feathers, combs,
and even crowing in a hen turned rooster). However, this is not a
true sex change because the bird cannot fertilize eggs. On large
farms of 10,000 or more hens, this has been definitively
There are some animals that actually change sexes, but the
chicken isn't one of them. I recall a marine biologist I once met
telling me that all very large groupers -- the ones that weigh
hundreds of pounds -- are females because only mature specimens can
grow that large and all groupers change to females as they mature.
It's called sequential hermaphroditism. When males turn into
females, it's called protandry, and when it's the other way
around, it's called protogyny. Only fish and some
invertebrates demonstrate sequential hermaphroditism.