I left my chickens in their coop today as it was raining. They are about 5 weeks old. I have a mix of cornish cross with rainbows and australorps. It cleared up in the afternoon so I went to let them out and was horrified to find almost every cornish cross was running around bloody while the other breeds were fine. They had been pecking at the cornish cross all day!!! I don't know how to fix this! HELP!!