I had 10 chickens, 8 hens, 2 roosters. 5-6 months old, all raised together. 2 were Spitz hens, so they were quite a bit smaller. 2 days ago I notice one spitz dead under the roost. No apparent signs of injury. Since then, all other chickens pick on remaining spitz. She hides all day. When I try to get her out into the run, the others charge her causing her to flee into coop. Any suggestions?