Always soak the pellets, because horses can choke on them and they are hard to chew dry because they suck all the moisture out of the horsies mouth... As for colic, they will not "expand in the tummy and cause it to rupture.. this is just not possible. What they can do though, is dehydrate the horse if he doesnt drink enough water..depending on the moisture content of food, horses drink more or less water. I always thought you didnt have to soak the shreds, but I have never feed them so I dont know for sure.