I'm new at raising chickens and am looking for some suggestions on what could possibly be wrong with my (maybe four week old) pullet as well as possible treatments for her. She doesn't seem to want to walk and when she does walk, her steps are very short in comparison with the other chicks'. She will walk a few steps then sit down. Additionally, she seems to be very slightly knock-kneed. She doesn't seem unhealthy beyond this and is eating well. She does, however, sit when she eats. I don't think this is something that just popped up today, but rather just became severe enough that I noticed it. Prior to today, she seemed normal, but I had noticed she was always the last one to do anything -- chase a bug, run after the others etc. It seemed like she was consciously deciding if she wanted to participate. Now, I think it might have been this walking thing working on her. Any suggestions?