Please help! My chick, Finny, is limping and sleeping a lot! She is about 3 weeks old and has been healthy, if not quite small. She's at least half the size of the other chicks I have. This is my second flock and I haven't had any of this happen before. She's been picked on before by the others, so that may have caused it, but I have no idea how to treat it! Her foot and leg looks fine, no signs of swelling or injury, but she's limping. She also was sleeping on the other side of the plastic tub we use to brood our chicks, far away from the lamp. I'm scared she might be really sick and might die, she's very listless and won't move around a lot. Please help!