I have two ducks in a coop i built for them and just recently I've been noticing tons of flies which is really disgusting to me, and I'm afraid my ducks can get worms or parasites in them from the flies. I clean the ducks pin every two days and now that the flies been coming around i clean them out every other day and their water bowls and pool is changed every day and sometimes two times a day on really hot days. Is their anything i can spray back their that won't harm my duck, or something i can spray back their overnight and i can move the ducks back in their pin in the morning. I do have a Tractor Supply here in town that carry a supplement for flies thats for live stalk but I'm afraid to use something that Im not positive will be safe for my animals. PLEASE HELP ASAP!