We love our barn swallows too. Not a mosquito to be found, and we have marsh with standing water less than 300 yards from the house.The only use that it gets is that the barn swallows love it. I will miss that part. The old barn has been home to who knows how many swallows over the years.
Call me crazy....I'm already looking into some sort of swallow structure when the barn comes down. Swallows are a big reason I want to wait until September to take the barn down. A lot of nests with eggs in them now.