Hi there, My wife and I have noticed that our barred rock, named Bad Rock, hasn't looked great. She doesn't walk far before she sits and when she does walk she has trouble walking and she tucks her tail down as well. she has started sitting away from the rest of the hens in the coop at bedtime and she hasn't layed any eggs in a while maybe 3 weeks or so. What is it? What can we do? We don't know how old she is, she is at least a couple years old if not more. She also has lost weight, she doesn't seem to be eating and she isn't active or talkative and she doesn't hang with her best friend who she was inseparable from.