Grain Feed - What it is for and How to Use it

[bcrosy]

Does anyone know what grain feed is for, and how to use it?
I tried the medium trough feeder, and the large one, but they don't take grain feed. At this point in the game I have pigs, cows, sheep, goats, alpacas, and rabbits. It may be the case that I need something to spread it with, but I can't figure out what.

Any tips you can give would be helpful!

[beans]

Grain feed is for horses, and need horse food trough. But where's the horse? You'll unlock them later in the game.