We are having trouble with pecking and pulling feathers. One bird in particular seems to be the aggressor but even with her put in chicken time out, the others have pecked at our wyandotte to the point of drawing blood around her tail feathers. We have 10 hens together in one coop and they are mixed in breeds. 3 production reds, 4 rhode island reds, 2 barred plymouth rocks, and one silverlaced wyandotte. The wyandotte was isolated and the wound healed but her feathers had not grown back over. After reading on the forum, we tried blue-kote and it worked for just a few hours even after reapplication. We bought flock-blocks and installed a bug zapper over the pen yesterday. Four of the hens have begun laying and the other 6 have not. Any thoughts as to causes or methods of stopping this behavior. It is to the point of isolating several chickens. Do we need to separate by breeds? We also have 5 smaller chickens that are in separate quarters that we would like to try to move together at some point. That is not looking promising at this point. The heat has been terrible the last week and that is when the pecking has started to become violent. HELP!