I'm wondering if anyone has tried boric acid for mites. It basically breaks down the exoskeleton of arthropods (insects, mites, spiders, etc.) upon contact, and is harmless to mammals, provided the acidity is not strong enough to cause an acid burn. It is sometimes used for antibacterial purposes in eye drops (in the proper concentrations), and some folk use it for a soothing foot bath.
I have used boric acid to kill ants and silverfish. They cannot become immune to it, so, provided they are in direct contact with it in some way, it will be effective. I mixed the powder with sugar water to feed the ants, and dipped paper in it, then dried it, for the silverfish. Cockroaches might be equally affected.
I've considered putting some boric acid into the sand where the chickens take their dust baths, but worried about them getting some into their eyes--and it can be strong enough that one would not wish to do that!
Has anyone actually tried this for mites, lice, etc.?