I have a mixed group of birds ranging from my 11/2 yr old girls, to some 6 month olds, and 1 lucky rooster that was mixed in with our last shipment....a few weeks ago I started noticing that I had a barred rock with a bright red botttom, otherwise healthy-didn,t think Too much of it until the red started to spread and she started losing feathers around the red skin. It then spread VERY rapidly to almost everyone. I have cleaned and disinfected the coop. Talked to a more experienced "chicken" person who said it was mites. I dusted with 5% Sevin powder 5 days ago, will dust again after 7 days have passed. Their skin seem less red, but I have noticed that some are starting to lose some feathers around their combs, can't dust that close to their eyes...any suggestions. The original bird seems to feel ok, but she looks awful, and they are all on the thin side. They have lost weight VERY quickly. I have food and water available at all times, they are being fed Layena- just switched the young one off starter when I put everyone together about a month ago. Thanks for reading my long winded plea for help!!