I've had to keep one of 5 Orpington chicks in a separate brooder from the other for since day one. He was born on April 28th along with two others that mysteriously died. Now 4 more hatched in the last few days and I tried to put them together and he was pecking them all! After only a few days he already does the rooster strut too. 100% certain he is a roo! The other 4 get along perfectly together even taking turns preening each other. The oldest of the four figured out how to use the feeder and waterer her first night, and is now teaching her sisters as well. Got 4 more getting ready to hatch any time now. One is already working on it as I write this. We already have a flock of 10 adult chickens. 6 Ameraucana hens and 4 Orpingtons, one of whom is the daddy of these new little ones. It's certainly been an adventure so far!