DE didn't work for me and Elector PSP is great but very expensive that is why I use permethrin. It works and costs way less. I had mites and a lot of flies. I used permethrin concentrate, mixed it with water in a sprayer and sprayed in the coops thoroughly. With the mites, it does not kill the mite eggs so repeat spraying is necessary. There is no egg withdrawal period. To my surprise was it also eliminated most of the flies. I have way less flies now. If you have a TSC they carry the permethrin powder, premixed spray bottles and the concentrate. 

