I kill the mites around the animals before they can bite and to get rid of them thoroughly you have to treat or sterilize the surrounding area anyway. I don't put the DE on the animals except in some cases. If the avermectins (ivermectin, revolution, etc...) or advantage are not possible or the animals suffer too much blood loss and irritation from the bites before the critters die then I will rub DE in their fur. I had rat mites indoors and all it would take is one female reproducing and overnight a gerbil tank would fill with so many mites they could send the gerbils into shock and seizures. I actually only found one still alive and twitching. The rest dropped dead in 12hrs or less of being stuck in a glass box with all those newly hatched mites. I still didn't DE the gerbils directly though. I put a layer in the cage while changing bedding so the gerbils would come in contact with it in the bedding and the mites would not live in the bedding. For chickens I'll put it in their favorite dust bathing spots. Of course this doesn't really work with wire bottom cages since there is nothing to hold it where the animal will get into it on their own so it's less effective as a rabbit treatment in those situations. Beyond that I coated the floor, some in the food which also took care of those pantry moths like I said, and so on. That way hatching parasites that fall off or try to expand from one cage to the next all die and secondary hosts like pest rodents cannot carry them. Actually dusting the animal itself I consider a fairly weak long term solution. It can cut a parasite load immediately and like I said was useful when the mites were killing my gerbils faster than the ingested meds could kill the mties or it can be a good preventative if majority are not showing symptoms yet so you don't want to expose them to chemicals unnecessarily but you get a more thorough die off with repeated ivermectin or 1 dose of the meds that last a month long. You also don't have to worry about the animal and just keep the surroundings clean for an entire month with revolution. More expensive but drawing it out with a syringe 1 large dog tube treated everything I had including dozens of guinea pigs and gerbils. DE will fall off and ivermectin will only kill for a short time so you have to keep treating again for 3-4weeks to get every egg that hatches until they are gone.
My extra problem with rat mites that isn't as big of deal with fur mites is the secondary host. Fur and mites that fall under mange are often species specific but the 2 rat mite species and 1 mouse mite species are not. The pest mice will bring them back in or fail to get in the DE so it's never ending. I finally ended it in an odd way. There are predatory mites that will eat all other mites and many other small critters. They are often used as a nontoxic solution around reptiles and I'd just started keeping reptiles. I didn't buy predatory mites specifically but setting up naturalistic enclosures I used some yard soil. Turns out my soil is just jam packed with mite species. It's rather insane. I have grey, white, brown, black, red.... I could see them running around next to the glass. Happens some of those were predatory mites. They spread from the tanks through the house and eliminated the mites on EVERYTHING. No more mites can live in my house at all. I was even treating skin irritation and infections on the cats, a dog, and myself. I thought I had bed bugs, then I thought I had scabies, and then I found the rat mites just coating my arm after being around the small animals. Nasty buggers. Makes you glad to have fur mites for as durable as those guys can be.