When my birds were infested with mites, I treated them and their coop for a couple of weeks with DE and they were still loaded with the mites. At first I thought the birds were molting but they weren't getting their feathers back in and that is when I discovered the mites. I was afraid I might loose some birds if I didn't try something else. I did a little research and discovered Elector PSP which is quite expensive and Permethrin which cost way less. I started treating the birds with the permethrin and the coops too. After treating the birds and the coops with the permethrin they slowly started to improve. Eventually they got their feathers back in and no more mites. I had a lot of flies in the coops and as an added bonus it also eliminated the flies. I'm Glad the DE worked for you Permethrin worked for me and there is no egg withdrawal period.