..Is she new to your flock?
...My second question is do you have a new rooster that has started to try to mate and be rough with the hens? teenage Roos can be quite rough on hens!
Yesersonally would make sure that she is healed fairly well before I put her back with the flock myself
Yes, I picked up a group of 5, 6 month old Ameraucanas about 6 or 7 weeks ago, and this is the only one experiencing any problems. I do have several roosters in that age group, but as I was watching, it was the other hens pecking at her, even some of her sister Ameraucanas. This one marches to a different drummer, almost constantly bobbing her head up and down, like she is listening to a tune only she can hear. To the point that I started calling her Bob. She also seems to never look down, even while eating. When she eats, she keeps her entire head parallel to the ground, so she is really pecking blindly at the food. With her cheek tufts I can't see how she can locate any food, but with enough in front of her, she does get some down. She seems otherwise healthy, but socially, she seems to be in a world of her own, pretty much ignoring all the other chickens.