I'm with chfite--the disposable trap works quite well, not only for the chicken coops and brooder pen, but also for the front yard under my Mulberry tree. I hang two traps there. All I need to do is keep adding water to the bag--up to the line on the bag--and they work for a few months UNTIL they fill up with dead flies. I use a plastic bag and cut them out of the tree--I use fishing line--to dispose of them. No fuss no mess. They keep flies away from the front door of the house, too. We had a Texas BBQ a few weeks ago and had to move the two traps from under the tree to near the garbage can--about 50 feet away. We had no flies to contend with. The flies were all bee lining to those two traps hung on the chain link fence. Here's the Home Depot advert for it:
http://www.homedepot.com/p/RESCUE-Disposable-Fly-Trap-FTD-DB12/100083352#.Ubk0_WjnbIU
This is great info, thanks. I was just wondering what I could use to keep those flies at bay. We've hung the fly strips in and around the coop, but frankly have been unimpressed. Had a girl with fly strike a few months ago, so that's why we tried them. I've used DE in the coop & their enclosed chicken yard with great success, but it was so wet here in PA recently that it wasn't really working for the outside. I like the idea of being able to hang it somewhere outside, away from the girls
Another wondrous fly killer is Golden Malrin, which is manufactured to kill flies. I keep some of this inside an empty 2 liter soda bottle hanging in the feed room and tool shed. The bottles do not have caps and the flies access the bottles that way. Do a search here on BYC and you'll discover other uses for this stuff. Suffice it to say that several skunks no longer prowl around my coops at night.
Shannon