I have 2 chickens that are about 10 months old. I recently brought 2 more chickens from a hatchery, they are 16 weeks old, one is quite smaller than the other. I was told that they would be ok to be put intogether, however my existing 2 are really pecking and bullying the smallest one. They team up in the coop and peck her and she is already missing her tail feathers when we got her...What should I do? I feel really awful when they peck her so I try to push them away from her, but they keep doing it...Will I need to send them back to the hatchery??????HELP.