I have about 30 chicks in a brooder. There are several different breeds, but all the same age-3 weeks old. They have all 'grown up' together. As of today, my only 4 white cochins have had all their tail feather plucked out by the other birds. They are bloodied. I put some antibacterial ointment on them and separated them from the rest of the group. Now they are picking at each other. What do I do?