Got six chicks just before Easter. One has grown quite faster than the other five. About 3 weeks ago the others began pecking at him/her. I separated them in their tub and reintroduced them after a few days. All was well for a week or so and then he/she became "hen pecked" again. They are all now outside in a much larger pen while coop and run are being finished. The larger one is still separated and I'm not sure being pecked is all that is wrong with my chicken. The back end, on either side, is pretty bare, but other than a couple other pecked spots it seems ok. What else could be wrong?