They're still on "start and gro" so protein is pretty high (I'm at work, but I think it's 21%). I'll have to keep an eye out for the pecking, and try coating her back.
Second year with Chicks, and when the runt-ish chick of the group seemed to be missing feathers from her wing, then her back, we figured she was descending the pecking order and treated with some neosporin. But it was always a bit odd, since there was no blood.
Now she's still the smallest...