we have a 2.5 week old australorp that is happily living with another 2.5 week old and 3 more 5.5 week olds (easter eggers, barred rocks, and cochin), all of these get along fine. we had separated another cochin and another barred rock because they were pecking the others and the chicks. so, we are trying to slowly introduce the two pecking chicks in with the other ones. we tried to introduce the cochin in with the others. she seemed to be doing ok. my mom was supposed to be watching him, and later noticed that she noticed that one of teh 2.5 week olds was bleeding. the cochin had been pecking out some of her tail feathers. we have since removed the cochin again and the little 2.5 week old is separated as well. we washed the blood off, but it still looks very irritated. we need help as to what to do at this point. we are really frustrated with the cochin and the barred rock that keep attacking the other chicks.