I have eleven mixed breed hens. My coop is 10' by 10' and the run is 16' by 20' plus they have access under the coop. I have put out cabbage for them to peck and also a couple of small boxes to put clover and other greens in. My question is this. Several hens have the feathers pecked off just in front of tail feathers. A couple have the feathers pecked off on their backside around the vent. How do I stop this before it gets out of hand? I did have a rooster who seemed to be the culprit so I got rid of him but the problem still persists. Any suggestions?