A friend of mine has a large new barn that he is using for a coop. In the barn are smaller cages where the chickens stay most of the time. The have never free ranged except for a little dog run on the end of the barn. He cleans all the cages and the barn every two weeks without fail. He feeds and waters every morning and evening. He is very picky about the cleanliness. Why then does he keep getting a mite infestation? When he finds mites, he treats birds, cages, and coops with sevin dust. I dont do half the cleaning he does and I never have a problem with mites. He's got those tiny, little red and black mites. What is the cause of these and how to get rid of?