I have 11 hens and 1 rooster (and 4 ducks) all since the were 3 days old. So they've all grown up together. The hens and rooster are black sex links. The roo was an accident, they were all supposed to be females but we've never had a problem who him until now. Any time there's been an issue with bullying or pecking, we've separated them and after putting them back everything was fine. At first the ducks tore a bare spot on the roo and the other hens started attacking him so we permanently separated the ducks into their own pen and let him heal before we put him back with the other hens and everything was fine until one hen started up again. I separated her (and then the other two that also were being jerks) and when I put them all back, just the one hen was attacking everyone still. I gave her a few days by herself, even at night (which I never have had to do even when they were separated during the day they did just fine at night), but when I went to put her in the pen today, the rooster started attacking her. Not mating, attacking. Yesterday was the first day I've seen him attempt to mate with one of the hens so I know the difference. He was attacking her and she was running for her life. When I picked her up her comb and face were bloody and she was relieved to be separated. I don't know what to do. They are 4 months old now and will be laying soon but not yet. He does will with the others (though one hen I periodically have to put in time out because she's being an ***), but I don't want to have to permanently keep the one being attacked separate from the others. I'm at a loss on what to do. Thank you for your help.