I've never had lice, mites or ticks in the flock in the almost six years of having chickens. About five years ago, I rescued a rooster who was infested with lice and we found them during his 5 week quarantine. His bedding was removed, new bedding put down and he and the bedding was sprinkled heavily with food grade diatomaceous earth. Never have seen lice since that time. The nests always have DE in them, they have great dustbathing dirt under the coops and elsewhere and on occasion, I dust the birds with DE as well. It's the only thing I've ever used on the birds, though when we clean out the coops, I use Orange Guard (orange oil based natural insecticide) in the cracks and crevices. If an infestation suddenly came up, I might get poultry dust from the feed store if I could find it and DE didn't do the trick, but so far, have not needed to do that. There is a lice/mite spray they make for parrots I see in the pet stores.