I have a horrible problem with flys. There is a huge CLOUD of flys in the coop and it is driving me CRAZY. I think part of the problem is that I have a tree next to the coop that is just full of flys and always has been, even before the chickens. What can I do to get these flys under control?Here's some details about the coop if that helps at all-my coop is a 6x8 tin shed with air holes and a roost, and I use pine shavings for bedding. Any ideas?