Hi. A few days ago we noticed that one chicken of ours was unable to walk properly (she seemed to be hopping around on one leg). She is not eating that much and there doesn't seem to be any injuries or swellings on her affected leg. She can barely even hop now and hasn't laid an egg for a few days now. (she's over a year old) She just sits around now and sleeps a lot Does anyone have any idea what may be wrong with her? Thanks in advance for your help!