Not with chickens, it shouldn't. Even from being chicks, they'll have a strong interest to pursue anything flying close enough for them to snatch it up. I have my coop next to a pond that has an exorbinant amount of mosquitoes, deer flies, etc. They love it when a fly enters the enclosed run area (and quite comical to see an entire flock go stampeding after it).
I have noticed a decrease in the number of insects directly around the coop/run area recently (maybe they're getting smarter).
The flies here are HORRIBLE. PLEASE post your trap! We have fly strips, fly bags and the little yellow cardboard sticky things and they are still bad. We've ousted the compost pile hoping to stop their breeding grounds.
my girls ignore the flies. I hang a stickie strip in the coop and I also make it a point to hose down their outside area at least everyother day to breakup the poops so the flies don't have anywhere to land for long