I've read on here that you need to clean your coop out completely, remove everything, white wash the inside walls, etc, & neem oil for the roosts & little spots you cant get the white wash into.
Wood ash is mite/lice preventive for the chickens.
And I believe that mites can be in straw or hay (I forget which)
Coop is sealed and painted, cleaning tomorrow, can't get neem oil, but CAN get wood ash, lol. I know they can live in straw, but they were living in everything else too, so that's why I'm using it.