Sex Change in Poultry
In a normal female bird only the left ovary is active. Due to infections or other problems, this ovary may cease to function. In that case the right overy becomes active, but for some reason produces more testosterone and causes the bird to develop male plumage and secondary sex characteristics, although it will never become fully male.
Some examples are found below.
"Kristina Kwacz" -- this utility Buff Runner has undergone a sex change -- note the drake feather. She was a '98 hatched bird and developed the male plumage and stopped laying in about 2001
On the left is a 1992 picture of Lucky's Black-shouldered Peahen, on the
right pictures of her change in 2007.
Photos courtesy of Lucky Newton
This is a female Red Golden that started to change to male
plumage after a couple years of laying. At this point (around 6) she is still
laying. First signs, 3 years ago, were her crest turning orange (not gold like
the male) and she got a long male-patterned tail. Each year since she's gotten
more male plumage, tho' not quite the normal coloring. The male she is with still
courts her.
Photos courtesy of Jan Peterka
Direct questions and comments to Barry at FeatherSite -- questions and comments