In my experience strong herbs work wonders.
http://www.grit.com/farm-and-garden/marigolds-and-chicken-mites.aspx I found this about a marigold wash.
Mint or Rosemary are great too. I planted basil, rosemary, mint, garlic, and marigolds around the coop. I hang rosemary inside and you can mix dried herbs into whatever material you use for bedding- dust baths too. Its more of a preventative thing though. I've had chickens for several years and never any bug issue, besides the darned flies in the run.
http://www.grit.com/farm-and-garden/marigolds-and-chicken-mites.aspx I found this about a marigold wash.
Mint or Rosemary are great too. I planted basil, rosemary, mint, garlic, and marigolds around the coop. I hang rosemary inside and you can mix dried herbs into whatever material you use for bedding- dust baths too. Its more of a preventative thing though. I've had chickens for several years and never any bug issue, besides the darned flies in the run.