All horse owners have different ways of feeding, and American Curly Horse owners are no different. There have been many myths about Curly Horses and one of them was that they never need hard feed. That simply is not true. American Curly Horses, depending on where they live, and from where their hay comes, usually need some vitamin and/or mineral supplement. In Vermont, we are deficit in magnesium, as are many places in North America, so it is important to choose a feed that will supplement them well. Because I prefer to have greater control over what my horses eat, especially regarding non-nutritive items in feeds, I mix my own.
I have chosen to feed my horses a higher protein and fat mix, and adjust the carbohydrate need for each horse. But, I primarily used the hard feed as a carrier for the supplements I have chosen to use. For the past four (4) years I have used a vitamin/mineral mix from EquiVision that has kept my horses doing very well. I chose it because it came closest to the amount of magnesium, selenium, and vitamin E that my vet had suggested would be best. It also does not have fillers. However, I have found that three (3) of the horses have needed a bit higher magnesium, for various reasons, and so supplement them with a pure magnesium powder.
Ultimately whether you have a Curly horse, or some other breed, it is best to consult with your vet, and research, research, research before choosing how to feed your horse.