Take a gallon plastic milk container. Save the cap.
Cut 1 inch holes around the middle. 4 or 5 should do. I try to cut the holes on three sides and not the top so the top flap acts like a rain reflector.
Find the stinkiest chicken poo you can. 2 are even better. Scoop it up and scrape it into the gallon container through the top.
Sprinkle 1 tablespoon Golden Malrin inside the jug. Hang by the handle near the coop and run. NOT INSIDE.
Before you know it you will have over an inch of dead flies. When that happens add more poop and another tablespoon of Golden Malrin. For bait on the second level you can also use a tablespoon of uncooked ground meat.
I stole this from another poster. Forgot to get their name, but I can`t take credit for it. best idea I`ve seen........Pop
I saw on a science program the other day about a home made fly repeller. You are suppose to mix basil and cat nip about half and half and then put it in a nylon stocking and hang them about. Supposedly this repels flies. I haven't tried it yet but plan to next spring.