You can mix up some Pyrethrum in a one or two gallon pump up garden sprayer and it will work against these mites. At least it will if you get good coverage.
The mites infect the feather follicles in the same manner that human eye lash mites colonize the hair follicles on our eye lids. I also expect that mange is closely related to depluming mites.
This supposedly causes the hens and roosters to poll their own feathers out by the roots in order to get some relief.
Another way if you have a large number of birds that are easily accessed is to mix up the insecticide a dip tank. A plastic 39 gallon garbage can makes a good dip tank, and give all your birds a quick baptism in the Pyrethrum dip.
Another way is with a pour on pesticide.
Things like DE or a dust bath is quite useless when treating for depluming mites.
Besides being an insecticide Pyrethrum is a powerful insect repellant. You will get better coverage by spraying or dipping your chickens after dark.
Finally, once you are done with your poultry dip your pets. Fluffy, Spot, and Old Troop all 3 can use a little help with fleas and the mange.