I have 6 three week old chicks. They have living in a cage in my garage till the coop is done and they are older. When I just went out to check on them cause I do several times a day. One is bleeding from his tail feathers and the others were pecking at it there. We separated the one from the others and they are chirping like crazy now and another one is starting to pull out her tail feathers. What is going on with these chicks? I am a newbie. What does this mean and what should I do? Thanks