I have a 3 month old hen that I am trying to introduce to my two five-month old hens. I have tried to gradually introduce the younger one by giving them time to roam around together outside and keeping them separated by chicken wire in the coop. A few days ago I went for it and allowed them to intermingle in the coop. Shortly thereafter the youngest hen started getting attacked as the other two hens pecked on her. It was violent and hard to watch. What should I do? Is it possible for them all to get along and live under the same roof??