Fiberpsyll 4-in-1 Digestive Aid for Horses, 5 lbFiberpsyll 4 in 1 may help prevent sand colic. Adds bulk fiber to the diet and provides digestive support. 4 in 1 formula contains psyllium, wheat bran and beet pulp for bulk fiber, plus probiotics (direct fed microbials), prebiotics (mannaoligysides) and live yeast to support digestion. Supportive enzymes benefit the digestive system, working in tandem for healthy digestion. Research has shown that providing microbial support greatly improves the