I have bought 22 chicks at a swap 3 weeks ago. I was told they were all 2 days old and Ameraucana and barred rock. I suspect there are some others mixed in but I'm pretty new to chickens so I'm not sure. They are just for pets/eggs so it really doesn't matter. Anyway they are all growing and doing great except for one. This little baby has not grown at all! She is the same size as the day I brought them home. Eats, drinks and acts perfectly fine. Feathering out just like the others, at the same rate. Just not growing in size at all. Is there anything I can do? Something I'm doing wrong?