There may be something wrong with that one chicken that the others sense. Or you may have a few bullie that need to spend a few days in chicken jail to lower their status in the pecking order.
Yes, but that doesn't mean that you don't have a bully. In my first chickens, I had a young cockerel who was the leader at a young age, crowed at 3 weeks, got along with everyone. At 5 months he developed a limp, quit crowing, became a coward, and even my banty hens started joining in with the others to peck him and chase him into hiding spots. We finally culled him at 6 months because I think he had a bad heart and we couldn't watch the bullying anymore. Sometimes the others know one is sickly.
Ok well it's all hens doing it to another hen.. I just don't know what to do with it and if there is something wrong with it and they try to kill it wouldn't be right