One of my silkies has a bald spot on the back of it neck which at first I thought it was a bully, but now I wonder (because it keeps itching at it) could it be mites or something? They all seem to scratch/itch a lot. Is that normal? Should I offer a dust bath with diatomaceous earth? They're almost 3 weeks.. Are the top young to have mites? When should I start offering them dust baths? New to raising chicks so I just truly don't know what to do..