Another player on the fly breeding scene is damp hay chaff. Remember to pick up things like grass clippings, clumps of dead weeds, and especially hay chaff in areas it may become damp from ground moisture, 2 to 3 days of rain, urine, or water tanks. Hay chaff is a something so often overlooked yet so important to clean up off the ground around outdoor feeding or simply from moving hay from your barn to feeding area. It can become a serious fly breeding problem area notably if you're getting rain or even just high humidity.
CLEAN UP HAY CHAFF and other decaying vegetation before your biting stable flies breed and take over.
Dumping water troughs (as pictured above) can create damp areas long enough to not only create hay chaff but likewise mosquitos... Mosquito larvae takes about a week to get to the pupal stage, so if you dump your tanks, consider doing it only once a week allowing the ground to dry OR you can use Mosquito Torpedoes.
On a cleaning and no fly note, you can also use Bye Bye Odor around your stable to eliminate urine and other odors that will attract flies and, if you still haven't done so, make sure to renew your Fly Predator order for this season.
Happy Spring!