I am fairly new to the raising my own chickens and could use some help from some of you more seasoned folks. I have a family of 16 chickens that all grew up together. They are about 10 months old and laying about 12-13 eggs a day. They have a nice big coop, protected run that is twice as big as their coop, and suddenly the chemistry of the group seems to have changed. I went to my coop mid morning about a month ago to find one of my two barred rocks dead in the run and it was obvious she had been attacked. We weren't sure who the culprit was at the time. The next day I went out to find my other barred rock hiding in the corner of the coop with her head having a 2 inch area on the back of her head completely void of any skin and bleeding profusely. I took her out and put her in a 2x4 brooder box to heal. I wasn't sure she was going to survive but she is almost completely healed with all of her feathers growing in nicely. I put her in the yard in the day to get time to roam, but she can't stay in the brooder pen. I decided to see if she would be accepted back in to the coop and went in with her. The instant I put her in my Americauna rooster came after her and as soon as he started my buff orpington went after her as well. They weren't just chasing her and pecking. If you can imagine a chicken gang fight, this is what was happening. My son and I were able to chase the others off and get her out without any damage except for some ruffled feathers. Obviously I can not put her back in the coop. Any suggestions? Anyone know what may have caused this? Thanks in advance!