I don't know if the DE works, since I have always used it, and it may have prevented the problem from starting in the first place. I sprinkle it with a screen top shaker all over the shavings inside the coop and gently mix it in once a week, and replace all the bedding inside the coop twice a month. (It's pretty small, only 4'X6') I do the same to the chicken run, which I use triple shredded mulch in, but I don't replace the mulch, I just mix it and turn it with a rake once a week. The run is roofed, so it stays pretty dry. Also, I take a bar of soap once in awhile and rub it all over on the underside of the roof (the ceiling) in the coop and the run, and it's suppose to prevent wasps from building nests there. Also use a lot of DE mixed up in the dust box the chickens dust bathe in, and I haven't noticed any parasites. I did all this b/c a friend of mine who has kept chickens for years does, and never has had a problem.