Are horses scared of flys for real?

Horses are indeed afraid of flies, and for good reason. Flies can be a major nuisance, and they can also transmit diseases. Horses have a natural instinct to avoid flies, and they will often swat them away with their tails or legs. In some cases, horses may even become panicked if they are swarmed by flies. For the most part though, flies won't cause horses to do anything harmful or cause any other major issues.