Hi Chicken Obsessed,
I have found that keeping Guinea fowl with the chickens helps!
I don't have any mites on my layer flock, but I developed a problem with them on the 'spare roosters' as I call them, housed in a separate coop in my horse barn. {The short version of the story is that I lose Roos frequently to coyotes so I keep spares each year.} Anyway, last year a friend gave me some Guinea eggs and I ended up with three of them, housed them along with these mite problematic roosters and discovered they preen the roos, eating up all the mites in the process. The roos need to be kept tame, so I handle them each daily. This gives me a chance to inspect them for critters.
Don't expect Guineas to be great and friendly pets like your chickens, though! I have treated them with as much love and attention as my Chanty flock and they are still silly and fearful of me. When a stranger comes into the barn, or a new truck drives up in summer...wow loud and cranky!! Good watch-birds. Sadly, though, I still lose them to predators as they don't always come in when called like my chickens and roosters do.
Good luck!
kathy