We are 7 months into chicken owning and one of our girls has a missing patch of feathers at the base of her tail. This is new so I'm guessing she's being pecked at, though I haven't seen this happening. Otherwise she seems healthy. Should I be concerned? Separate her from the others? Or is this typical low-hen-on-the-totem-pole behavior? They are all about 6-8 months old.