when reading the text in your link just right after the sentence " may take the form of a male testes" my eye dropped and i saw the picture of that rooster in front of the narcissus and realised we both had the same expression on our face!Actually, hens do not only act like roosters, which does happen at times, they can actually change their sex. It's pretty cool.
What Google says about this.topic for chickens:
Most cases of spontaneous sex reversal are the result of a disease condition which has resulted in damage to the left ovary. Typically, female chickens only have one functional ovary, the left one. The right ovary and oviduct are present in the embryonic stages of all birds, but typically do not develop in chickens.
Ever heard the term cockerels?