How To Get Chickens To Stop Pecking Another Chicken?

[LUVMY5HENS]

I have one chicken that constantly gets pecked (to the point of bleeding) by the other girls. We moved her too a tractor with a new friend for about six months. Now we have gotten rid of the tractor and moved her back in to the main coop. And the other girls are right back to picking on her. Her poor back has got tons of feathers pecked off by her tail and is bleeding. She did fine when she was in the tractor. How can I get my other girls to accept her and leave her alone? Any suggestions would be greatly appreciated!