Curious, how did DE help you? I had northern fowl mites last year and I used spinosad. Sprayed the inside of the (wooden) coops and dunked every chicken I had in a bucket of the solution. One and done. Not sure if you're allergic to anything in that, but for future reference.May I chime in on the side of "give them a dust bath too?" I have had a very bad year battling red mites. Wild doves brought them in and I've been fighting them non stop now for 8 months or so. It's been hell. In the war against parasites? Give your chickens every weapon available.
I can report a 99% victory against the chicken mites at this point. But I will never again relax and say I'm mite free. It cost me my brand new chicken tractor, (burned it, too many mites and places for mites to hide) hours and hours of scrubbing with detergent and oils, constant vigilance and about 30 lbs of diatomaceous earth.
And yes I can report that DE does work, it's just not a 100% fix all. In your arsenal of weapons it can have a useful place, but it won't take the place of a lot of hard scrubbing, hosing, cleaning and finding where every tiny nook and cranny they hide in is and going chicken keeper postal on their red vampiric butts.
I could not use most of the chemicals available as I have several severe allergies and just can't take some risks with my health.