We have had some high temps recently, 100+ temps. I've noticed that we have had tons of fly's in and around the coop. I bought a bale of 3 way (oats, wheat and grasses) on the way home last night. Went out at 6:00 am this morning to beat the heat to clean out the coop's. At first I thought my girls had a very bad case of worms, but upon closer inspection the poop in the coop was infested with maggots. I cleaned the coops and put down the fresh hay, then drove into town to the auto parts store and bought 6 of those pine tree air fresheners in Vanilla. I had read here awhile back that the vanilla ones would repel fly's. Well when I hung them this morning the coop was full of fly's, by early this afternoon and just now, not a fly is in sight, and my coop smells like vanilla. It works!