When cleaning out the nest boxes, do you sprinkle Sevin Dust all around the boxes and then put the hay on top, or do you sprinkle the dust on top of the hay to keep the mites under control? I haven't noticed any mites yet, but want to keep it at bay. Also would you recommend sprinkling this dust in their hen haus? Their flooring is all dirt and a mixture of hay. Any help would be greatly appreciated.