During the summer months when there is plenty of grass, that should be enough for them. However, too much grass in the early spring can be very harmful to minis. They will overeat and get colic which can cause them to founder. Please limit them to grass at this time to just a few hours a day. If you stall them or have limited grazing areas, feed them twice a day. You can choose a feed for horses, such as a 9 % protein of sweet feed or just plain oats. About a small coffee can size would be plenty. Hay should be fed after graining. A small flake in the mornings, and in the evenings is enough. Make sure the hay you get is good quality “horse” hay. Hay that can be fed to cows, doesn’t mean it is good for horses. Horses have very sensitive stomachs, and can’t eat moldy, or hay that has been wet. Depending on your location, there are several types of hay, such as orchid grass, alfalfa, or just good grass hay. Fescue hay should not be fed to pregnant mares. (in our area, it can cause a mare to not make milk) Also, keep fresh water available at all times. Rinse out your water bucket daily. If you have a large tub, don’t fill it to the top, so you can change the water in it. A horse needs a lot of water, so not to get constipated and colic. Always watch your horse when you feed him. Observe how they eat. This will tell you a lot about your horse. If they don’t look like they are eating at the same speed or act funny, then something is wrong with your horse. A horse that does not eat should definitely be looked at for sickness. Even if you turn them out in the pasture everyday, observe them for a while before heading back to the house. If they don’t start off grazing, that could be a sign of something not right. For those of you who have large pastures and can’t keep your mini off the grass for long periods, I suggest using something such as the “Best Friend” grazing muzzle. This will allow them to graze, but can’t overeat until they colic and could lead to founder.
Minis don’t need a lot of space as a big horse does. If you have a large backyard and a small building or shed for shelter that should be sufficient. They like to be outdoors as much as possible. Please provide some sort of shelter for them with at least 3 sides to ward off the cold, wet weather. In the summer, they like to find some shade to get under also. If you have a barn to stall them, please turn them outside everyday for exercise. You will also need to keep the manure picked up and some sort of bedding, such as shavings or straw, which should be changed at least weekly.
This information is based on my knowledge of what I know from being around horses my entire life. It is a guideline, but please contact your veterinarian regarding the care and health problems of your miniature horse.