I have four hens left in my little flock of brown sex links. For the past 10 months they were inseparable, free-ranging all over. In the last month I have noticed that one is constantly in the nest box, and the other hens have ostracized her. They chase and peck at her whenever she is out of the coop. They all used to perch together, but now it seems as if she is not allowed to be part of the flock. She doesn't appear to be sick, but she is definately chicken-non-grata. For a while she would sit on any eggs that were laid, but now the other hens lay in another box. Don't know if I should let this go on, or take matters into my own hands; so to speak. Any ideas?