I've had that now and then with the black to black cochin. Don't have any of the offspring anymore. Dont' know much about it, but I think it is referred to as a mutant, a sport, but cool. I would like to know more about the white mutation. The white cochin female and male, as they grew, were the most beautiful, clear, snow white white. A coyote got one, he was a wanderer (this was back on the coast), never learned much and got ate, the other just up and died one day in the nest box. No prolapse, just died. I would keep any white that I ever got from a black to black mating, they are beautiful. Have a wonderful day, CynthiaM.