My birds have never had lice, except for the one adult bird I've ever bought-he came loaded with them. Dusted him and his bedding with DE and no more lice. Make a powder puff with one of a pair of knee high hose and DE, tie it off, and powder under both wings and around the tush in the "petticoats". Sprinkle it lightly in every nestbox, too, and from time to time, change for fresh straw and re-dust the nest. That should do it for the birds. For the coop itself, clean it out completely and get some spray Orange Guard natural bug killer to spray in all cracks and crevices, especially around the roosts. It smells nice and won't harm the birds--ACE hardware carries it and if they are out, they will order it for you. I got more today.