about 4-5 days ago I noticed the chick was laying down a lot and limping when she walks. Two days ago I noticed her "knee" joint was a bit larger than the leg she will put weight on. She still eats and drinks, but she's not growing near the pace of the other chicks. She's gorgeous and sweet and I want to do right by her. Please let me know what I should do to treat her. Thank you in advance!