My horses love this recipe served cold in summer, warm in winter:
1 handful oats
1 tablespoon salt
2 tablespoons molasses
3 tablespoons apple juice (optional)
2 gallons water
Proportions are flexible. If your horse is IR, make sure molasses is ok, or skip molasses and see if just apple juice will do. Play with recipe at home and see what your horse likes. Mine suck down extra water to get at the oats in the bottom of the bucket.