We put the hen that was attacked out on a leash cord. Have had her out for a couple of months. We put her in a building at night. She seems to like it. She is outside the chicken run so she sees the other chickens during the day. She don't get tangled up either.
You can remove the bully and put it on a leash around its leg down by the foot. Try using a small cord and put its' feed out by it. We had to do that to a chicken and it really worked for keeping it from getting attacked by other hens.