Well I have had my Pekin ducks (6 of them) for several months now and they are doing great. They love hanging out in the yard and are actually doing a knock out job on some weeds I had in the grass. But in their cage there are Flys that are pretty bad. I keep it clean and there isn't any poop sitting around. The ground of their pen is small gravel so I wash the poop and other stuff down through the gravel daily. The ducks don't spend much time in the pen in the day since I give them free range all day and only lock them in at night. Any idea how to get rid of these Flys? They get in my house and it's getting rather annoying Thanks for any ideas.