I have a hen about 3 years old and have recently noticed her favoring one leg and limping. Even with her good leg, she doesn't seem able to hold her back parallel with the ground. Her tail remains near/on the ground while she wobbles around. There is no sign of exterior damage to her skin and feathers (besides dirt from her rear remaining so close to the ground), so I am inclined to think this is coming from age or a disease? Anyone have any light they could shed on this? Thanks in advance!