Hi everyone! I am new to raising chickens and about four weeks ago I got 9 chicks. I know two of the nine are silkies and I am having a problem with one of them. The other is growing great, getting all of its feathers and actually growing but this one not so much. It is a lot smaller than all the other chicks, not growing feathers, and has something crusty around its skin. I have attached a picture to show what it looks like any help would be greatly appreciated, thank you!