This is Fifi. He was born a female, starting laying eggs..then one day grew rooster feathers, learned the mating dance, and started crowing at 5:30am. Easter Egg breed, he laid healthy green eggs.
A friend of mine had a RIR who went through the same sex change phenomenon. I've been around chickens for 71 years, and though I've heard about this it's the first time I saw it first hand. Such birds generally have an ovarian cancer/problem.