Big fly problems are a result of lack of sanitation and not keeping your horse clean. I recommend a good bath--I use Mane N'Tail bc it's cheap ($6)--then using a GOOD (that means pricey) fly wipe. I also put SWAT underneath their eyes and on their ears, and I use a rag to put fly wipe on my 3 horse's faces in the summer. When you horse stands quiet after this, you KNOW that you've done a good job. =D
Never mind... Ill figure something out on my own.
Maybe we will just do night turnout.