Actually, horses can colic rather easily. Unlike humans and dogs who can throw up when they get a tummy ache, horses cannot. I assume these people are referring to the form of colic called sand colic. This happens when you feed a horse on the ground where there is sand, and they ingest the sand along with the food. Even if the area doesn't look sandy, it can still happen. Grain should always be put in some sort of dish or pail to prevent this, or just fed by hand. ;-)

Horses can also colic by being fed too much after being fed too little, or by see-sawing back and forth, so you have to be careful in that respect. If there was one thing that got drilled into my head, it was the importance of keeping the amounts fed each day as exact as possible... this means measuring it out... every barn I have been to has used coffee cans to measure, and 1 quart means 1 quart... not a little under, and not a little over. It's dangerous to play around with a horse's food intake. Also, a horse that is not getting worked can do very well off of just grass and/or hay, especially if the hay is good quality... my horse has had his grain cut way down since I recently changed barns, and he's still getting quite tubby off of the rich hay that he gets. :)

-Darleen