I have 29 hens and the majority of them have the depluming mite. I have given them Ivermectin, dipped them 3 times in sulphur and a mite dip. The redness will go away and come back again. They are losing a lot of feathers. I'm at the point where I think I'm going to need to cull my flock and start over. Does anyone know of a tried and true treatment. Please note, this mite burrows under the skin. It is not like the Northern Fowl Mite. You can't see it. Dusting the chickens won't help. Thank for any help.