I'll have to see how she does this year. I keep her with a steady supply of mineral blocks with sulfur and she gets daily flax seed for the anti-inflammatory properties. So, maybe she won't need the fly sheet
I had to get creative this year because Oklahoma is allergic to fly bites. The sulfur in mineral blocks got rid of a lot of the little nippers, but needed something with some kick against the jumbo jet horse flies
Chunk horse spray + sulfur powder into a pump spray bottle. Took the horses awhile to get used to the spray wand, but it does wonder to get rid of the flies