The flies in my coop and run are becoming unbearable. Even after cleaning it out and laying fresh pine shavings. I read a post from someone who used permethin spray to get rid of mites and it also killed the flies. I found and bought this yesterday, but now I don't know if it's safe to use. If I spray the ground and wait for it to dry before letting them out, will it harm them if they eat something that has been sprayed? Thanks.