Hi, we keep just 4 hens and like most have had the occasional invasion of red mite, however with the warm humid weather we, or rather our hens have been overrun with the little monsters.
Having spent in the last few weeks around £40-£50 on diatoms, sprays, washes, etc. and following the instructions to the letter we made no progress and our hens decided that they were not going in to roost at night and frankly I cannot blame them, even putting my head near the door had me scratching and I decided that new and drastic action was needed and I came up with the idea of using steam from my wallpaper stripper, this is a 2.5 kilowatt model that holds about a gallon of water, I removed everything from the hen house, closed the doors, blocked the vents, and put the steam hose in through a gap and then watched it heat up like a steam room, after about half an hour I was amazed to see the mite appearing on the outside in their thousands, coming from gaps smaller than you would think they could get into and in such quantities even from under the felt roof that they fell like damp dust. While they were trying to escape they were sprayed with mite killer. After an hour the outside of the coop was averaging about 50 degrees and inside was around 80 degrees measured with a thermal imaging camera.
Afterwards, wearing gloves I used the steam hose in every crevice as steam gets where even water cannot and then finished off by going over the ground with the steam plate to finish off any others. Today I can see not a single moving mite, and in theory at least I should have killed the eggs off too. I will now repeat this weekly for a while to make sure no stragglers find their way back, the hen house survived very well with no warping.
One thing I have not seen mentioned about red mite is that the little horrors as well as crawling around also float very easily even in light air movement, they are really like living biting dust , I discovered this when I put a bag of rubbish into a bin with used bedding already in there, within seconds I was itching just from the mites that were blown up into the air from dropping a bag in, its no wonder they end up in our hen houses.
ChicKenKen