I have a 5 week old silkie with a scaly patch (no feathers) on her back just forward of tail. Another chick same age, a lavender d'uccle, Has no feathers at all except wing, and the skin under his baby down feels crusty. I don't see how mites are possible as they are still in the brooder indoors, and are not picking each other. The other 12 are perfectly fine. Any thoughts?