I have a 16x10 fully wire enclosed chicken pen. I'm not exaxtly sure it would be called a coop. It's equipped with fully covered nesting and a small place For the chicks to roost. I have 8 chicks. They are between 4-6 weeks old. I just put them out this week and the LOVE it. They also have a little house in there for them if they want some extra cover. So, as the days have gone on the flies are starting to gather in the pen. Mosquitos are also becoming a problem. They just seem to come with Floridas hot humid summers. Although I found something pretty cool we are going to try for the Mosquitos. http://skeeterbag.com/. I can't believe I have never thought of that!! Anyways, any advice in what to do about the flies? The floor of the pen is dirt although there is wire dug 3 feet underground so nothing can dig in. I would like to stay away from any harsh chemicals.