In my opinion DE is worthless. Some people swear by it and it's great if it works for them but I haven't had any luck with it. Permethrin is very cost effective and works. You do need to treat weekly for 3 or 4 weeks because it does not kill the pests eggs but will as they hatch out so repeat treatments are necessary. Also you might not see any pests during the days as some only come out at night and feed on the birds. I use a headlamp so I have both of my hands free and go out to the coops after the birds go to roost and inspect the birds. I also take out some paper towels and rub the roosts on and under with the paper towels and look for streaks on the paper towels which is also a sign of mites. Again, good luck...