Hello, today we noticed that one of my chickens is pecking several other ones behinds. All the feathers are gone in about a four inch diameter. We isolated the one that I think is guilty, but I wonder if this has happened to anyone else and how long do I need to isolate her? Why do they do this? No blood yet, but if she keeps doing it I am thinking it will be really bad. Thanks for 'yall's help!!!!!