Our local Guard routinely flies about tree top level over our house and pastures. Horses don't give a hoot. We've been riding and had the choppers come up over a treeline, luckily noone bothered to even flick an ear. The wind disturbance would be kind of like a violent storm to me, or that is how it seems when we get the down drafts from the really ground hugging birds. If your horses have been out in all kinds of weather, it shouldn't phase them.
We muster cattle here with horses and choppers. Most of them don't mind, the others only mind when it comes in low when we are Yarding up. Because it is above them, they don't do much other than put their head up and jump around a bit. If they have decent training then you can just keep them between hand and leg and you are fine. Posted via Mobile Device
WOW! Thanks for the responses!! I thought the thread had died, so I just looked at it, today. I think you're all right. My horses are familiar with the crop dusters and the local small planes, so it probably won't be a big deal the first time they encounter a chopper. Still, it's good to consider.
I'll try my big, industrial fan, for starters, preferably bc I already OWN it.