I've had good luck this winter with wood ashes from the wood stove with a little DE mixed in. I place this mixture in a cat litter box in the coop and refill it once a week. The hens have no signs of mites, but my roosters did have them about a month ago. Though my roosters I've never seen dust bathing all winter long. After I noticed the roosters having mites I started giving them a dust bath once a week. The mites have since cleared up.
