I have an 18 month old Welsummer hen who seems off. She was often henpecked by a rooster that is longer with us so she has always been a bit timid. Lately she seems lethargic and I noticed she seemed to have trouble with balance to the point she will stick out her wing to stay upright. Her comb seems a little light but she doesn’t have much of it left due to the other hens pulling on it. She is eating ok, drinking ok, joins in with being let out of the run enthusiastically with the others, but sometimes before I let them out, she just sits around , usually in a corner, with her feathers kind of puffed up and often with her eyes closed. Any ideas on what may be wrong ?