One of my chickens disappeared about 3 and 1/2 weeks ago, I thought something had got her. Yesterday she shows up and the other chickens started picking on her when I put her in the coop, which I thought was normal because they probably thought she was new. But this morning when I let them out she just drinks water and stays right in the coop on a perch. She is acting strange either standing in the corner, or standing on one foot or the other. Does anyone know what could be wrong with her? She is drinking water but I have not seen her eating.