I like this simple set up for a chicken coop. The box on the end is for collect the eggs so there's no fear of getting your eyes pecked out by a cranky roosting hen! Her site has other amazing ideas as well.
Around our place there is no such thing as a 'Fly Free Season' . Build the Cadillac of Fly Traps for a Fly-Free Summer says if getting this many flies- a good clean up of old bedding etc may be needed as well