I had a fly strip early on in my coop until my little cockeral got tangled up in one. I had went around the front of the house to fill up their water and when I came back around there he was strutting his stuff but I seen that something wasn't right. I thought "Oh Lord, he's broken his wing or something" but further inspection he had got caught in the fly strip! He's a pretty calm fella so I help him between my legs and untangled him. From my experience, until I got my leaky roof problem fixed I had a terrible terrible problem with the flies. The moisture I suppose gets the flies a breeding like crazy. Since the roof if now fixed I don't seem to have that much of a fly problem. I did hang a fly strip from the two corners that I could very easily reach of my coop. It does seem to help with the fly count and it's amazing what all other type of flying critters you catch on those things!