The chicken coop used to just be fenced in, but I've attached temporary plywood walls to the hurricane fencing to help protect my gals during the winter. I've also put flurescent lighting in the coop. Problem is, where the flies used to be able to fly right out of the hurricane fencing, they are unable to fly out now due to the walls being closed in. So the flies are doing a great job right now at "being fruitful and multiplying." I clean the coop and run regularly, so that is not the problem. Is there a way to handle that problem, short of using a can of Raid?