I too had two EE hens whose hobby was to walk up to another bird and yank out a feather. Then they would make the rounds to the other hens and repeat the deed. They did this often - daily; several times a day. All the hens submitted and didn't move or fight back. Sometime, if they'd pulled a small fluffy feather, they'd eat it so I increased their protein. But this went on for months. I gave them away to someone local who wanted them and who says they are doing well with her own hens. Now, all I have in the coop are doing fine. They do the normal whack on the head if a disliked bird is close by food, but no real feather pulling at all.