We got 3 new pullets about 2 weeks ago and initially everyone seemed fine. About 10 days ago the roo and other hens started picking on our ameracana- just figured they had to work out the pecking order. The "victim" started just staying up on a roost out of the other's reach but still eating and drinking. However, over the last two or three days she has become more lethargic. Today I noticed she is breathing very hard with her whole body moving (using "accessory muscles" in human terms) but beak is closed and she is just sitting in corner of pen (she is in isolation from the others). Doesn't seem interested in food. She's only about 16 weeks so she hasn't laid any eggs yet. Not sure what I can do for her-any suggestions?