I noticed a chicken with a lot of feathers missing on her neck so I started looking and there are mites, I know in the nesting boxes I saw them on the eggs. Now I see several spots on some other chickens too. I have poultry dust is this strong enough? How do I get that on the roof and walls of the coop? Do I put it in a sprayer? What about seven can I use both, poultry dust and seven? We can spray seven and I guess rub on the poultry dust. How many applications do you think it could take to get rid of them? I think they came because an egg got broken the the nest box and the yolk didn't get cleaned out (kids got the eggs). Thanks