I personally cleaned out the chicken coop, then powerhosed the whole coop including crevises (got the hosepipe right in). In the evening I powersprayed the outside of the coop.
Then at night I removed the chickens and put them in a dog crate, I went round the whole thing and sprayed any mite I saw with Poultry solutions Mite Kill Spray. They all died muhahahaha.
Then the next day I removed the felt from the next box and burnt it (bye bye miteys) and I covered where the mites under the felt (my mite stronghold as it were) with Diatomaceous earth. I dusted my birds in Diatomaceous earth to, annnnd I dusted the coop...all of the coop...including nest boxes and all the walls, ceiling, floor, perches, aaaaaaand straw.
I went a bit crazy with it really but that was a couple of days ago and I haven't seen a mite since...Still holding my breath though...its not over yet I am sure.
Phew what a laborious approach! Thorough deep cleaning will help enormously albeit after prodigious effort, however as meterman found a simple application of Milbenex (or there are other effective pesticides too which are licenced for pro use) in the house will have a longterm residual effect. Diatom is a good preventative too but won't cure a heavy infestation. Paint this on as a slurry add it to a dilute disinfectant base, stir to a light batter constituancy and paint on the perches and into every nook and cranny. Don't dust it as dust is very risky for chickens respiratory system and is a major vector of virus infection in the confines of a house. Also don't dust the birds directly for this reason and mites don't live on chx they just visit to feed so dusting the birds is less effective than treating the house and is dangerous to health.
If you are deep cleaning steam cleaning is far better than power hosing, if you've heard the story of the itsy bitsy spider you will know what happens after they get washed off and then they dry out, they crawl right back again. Use detergent when cleaning which will kill on contact only and has no residual effect. You can use Poultry shield or cheap washing up liquid as effectively.
Things to waste your money and effort on. I've tried all these with no or very ineffective results - top of the list is Barrier Red Mite Powder and spray which is expensive deodourant for chx at around £10 a pop whose active ingredient is a mosquito repellant. You can spray it on yourself and it will keep the flies off for 20mins or so but RM aren't mozzies or even insects and I've never known anyone who found these products effective in dealing with a red mite infestation. "Mite kill" a well named product. RM are very easy to kill, as I've noted, detergent will do it effectively on contact and so will Mite kill but at many, many times the cost. A £10 spray can won't last you one clean out and several repeated applications will be needed to be effective so not a solution on cost grounds. Blow torching - only effective on those on the surface and any hidden away escape to return again, satisfying though it is to do, but quickly reduces the interior to a charred black. Steam cleaning is better. Jeyes fluid an old fashioned quat disinfectant - the modern stuff isn't as potent as it used to be and I suspect has been significantly watered down to satisfy modern safety rules. Used neat it might work on RM but again seems to be only effective on contact when wet. You either love or loathe the smell but I've found the results on RM disappointing. Invermectin - will work for mites (like Northern Fowl Mite) and other parasites which live on the bird however RM don't, they only visit to feed so although this will kill them when they feed it won't attack them in the harborages where they breed and spend most of their lives. Also the nymph stage when they don't feed they'll be untouched. It will either take a long time to be effective if at all. I wouldn't bother with this or only use it in combination with other house treatments. See the reference for DE below which also discusses mites. The life cycle of RM is around 7-8 days.
The problem with killing RM is access as the little blighters hide in every seam and crevice which is why as has been observed felt is a massive no no in a chicken house. If you are buying a house and it has felt on the roof or nestbox you can be sure it was designed and built by someone who knew zilch about chx so you can quickly walk away from such a design. Felt is so well known as a harbourage for RM I wonder at the shear crassness of manufacturers who still use it.
So the answer is for a simple, little effort, long lasting solution use an effective pesticide (observing the safety precautions), or for a non chemical "organic" laborious solution clean, clean clean again every few days for several weeks then probably admit defeat and use a pesticide. Once clear, Diatom (a product name for diatomaceous earth DE) will discourage further infestations but don't dust it and although regarded as natural and safe by many, you should still use it with caution see
www.shagbarkbantams.com/de.htmBest regards
HF