Hiya, Amanda, and welcome to BYC!
We didn't have a fly problem until the farm across the road sold a few years ago to a lady with horses. We use horse bedding pellets in the coop so there's no wet poop in there so beats me why they were in there but you had to hold your breath so you wouldn't breath one in.
My sister who raises turkeys commercially put me on to this stuff. I just spray one dot on the window, and one on each of the walls. It lasts a month. The dead flies are safe for the chickens to eat.
It's pricey, but I bought my can about 5 years ago and it's still over half full. We've used nothing else. It does a wonderful job!
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