Save your money on DE. Permethrin garden dust will treat your chickens, placed in a sock or stocking and dusting lightly. They also sell ready to use permethrin spray for horses, or concentrated permethrin 10 (usually Martins or Gordons) that can be mixed with water, and used with a spray bottle or garden sprayer. There are different mixing directions for spraying chickens in warm weather, or for spraying the coop, nest boxes, and roosts, once all bedding is removed. The birds should be dusted twice at 10 day intervals to get the live lice and later, the newly hatched lice eggs. Permethrin spray lasts about 30 days in the coop, and the birds should be checked to see if a second treatment is needed after 10 days. DE is dangerous to breathe and to eyes, and I prefer not to use it, especially since it does not treat an outbreak of lice. It may be helpful in prevention, but not for an outbreak.
