The majority of the horses at my barn are fed sweet feed and we've never had problems with it. My horse gets a coffee can twice daily as well, with free choice hay (and grass in the spring & summertime). I wouldn't take your horse off the free-choice -- in my experience its the best thing for them. My mare has access to hay whenever she wants. Horses are supposed to eat little bits of food continually, not gorge themselves on meals of hay. With free-choice, the horse can eat more slowly, at a relaxed pace, making them less likely to colic. Its been proven as well that its better for a horse to eat from a natural stance, with his head down on the ground, instead of always reaching up into a hay bale. This helps with digestion.
You may want to re-evaluate his diet, as others have suggested, but I highly recommend keeping him on the free-choice hay.
There are tons of other factors that cause colic. Ask yourself...
- Is he prone to be stressed? Stress can cause colic. (Ie, is he nervous, spooky, spazzy, etc).
- Is he drinking enough water? If not, have some salt-blocks available (you can get large ones for the paddock) which will induce him to drink. You could also try mixing apple juice into water ... horses seem to like that.
- When he eats his grain does he wolf it all down or take his time? It's best that he always eats at a relaxed pace. You may want to put some large rocks into his feed bucket so he has to eat around them to get the grain.
- Make sure that you are giving him the right amount of grain for how much exercise he gets. Talk to your vet and evaluate his weight. If he's too fat with low muscle, he might need less grain and more muscle building.
- Do you have sand in your paddocks? This a high factor in colic cases. Make sure he is not ingesting sand.
- Are there any poisonous plants around your barn? This can also contribute to an upset tummy. You can probably find a guide online that tells you some poisonous plants to watch out for and remove from the fields (buttercups for example, aren't good for horses).
That's all I can think of for now. Hope things work out for you. Colic can be scary. *Hugs*