I adopted three hens from some neighbors that moved about a month ago. We noticed shortly after we got them that one hen had no butt feathers. This could have happened after we got her, or she could have come like this. Today, I noticed that she has a sort of yellowish crust near her vent. She's always been pretty skittish. Very hard to catch and pick up. Much more so than the cochin and the buff orpington. Also, I'm not sure, but I think she hasn't been laying. Any thoughts as to what's wrong with her? I've never seen the other hens pick on her. In fact, she seems to me like she's at the top of the pecking order. P.S. These are my first chickens. I'm very new to this.