Hello, unfortunately, when you take a hen out of the group due to pecking, what happens is, that hen becomes the newbie, so when she gets back with the flock, the pecking starts right away again. If you can put the bullies in the dog kennel, and let her back in with the group asap, that might make things better for her. A couple things to consider.....is your coop and run large enough? Is there plenty of room for her to stay away from those bullies? Are there things in the coop/run to keep the chickens busy, giving them something to peck at that isn't another chicken? Flock block? You can hang a head of cabbage in there and they'll just peck the heck out of it? You could even throw down a pile of dirt from the garden or a pile of raked leaves for them to scratch around in...