I just picked up some chicken from a farm. They were all kept in a barn, and hay was used on the floor. Some are missing all their tail feathers, some only a couple, and some are missing none. I got them on Wednesday. To me it seems like the are trying to set up who is in charge and they peck at each others tail ends. There was a lot in a small area. And I think that was some of the problem. Or could it be mites? But if it was mites, wouldnt they all be missing? Plus she had two different sections of chickens. And the other section was fine.