One morning last week while I was driving to work, I heard a fascinating story on NPR about Half-Hen/Half-Rooster chickens. You can read the story here. These oddities of nature are called
Gynandromorphs. And it doesn't stop there, this occurrence also happens in other species like butterflies, finches, and crabs. They are literally two faced, one side has the markings and characteristics of a male and the other side has the markings and characteristics of a female. The study of gynandromorphs in chickens is opening up the realm of how sex is determined in early stages of life. The story on the NPR website also has a few pictures of other examples of gynandromorphs in nature.