What breed are we?

[Lizmom]

Males cannot change to females in the avian world.

Ducks do change gender, at least female to male, according to Dave Holderread.

 

[Bo Garrett]

Yes, in the avian world females can develop a male sex gland and take on male characteristics. When avian females reach sexual maturity only one gonad develops, the other stays "undifferentiated" and can be affected by hormonal imbalances. This happens when the functioning ovary is damaged by disease or otherwise and produces a steroid which affects the undifferentiated gonad causing it to develop and become a testicle rather than an ovary. The bird is rendered, due to hormonal influences, into a phenotypic male but is a genotypical female. Males however, cannot accomplish this feat as both gonads develop into testicles and cannot be changed.
As a side note, the changed females cannot successfully mate as they have no way of transporting the semen to the female.

Blessings,

Bo