I guess I'm different. I've only had mite problems on sick birds or broody hens. Otherwise mine make their own dust bath areas, I don't add nothing to them. They tend to contain composed donkey or goat poop. They also dust bathe a lot where the donkeys have rolled and made bare ground. For the few I've treated I've used a pyrethrin based poultry dust and will dust in the nestboxes as well as any roost cracks. We also use barn like to keep things dried out, and will dust roosts as needed.