Since horses like the taste so much, bran can encourage picky eaters to clean up their feed. Bran can be fed in amounts up to 5 to 7 percent of the horse's total daily ration without causing harm. Balance out bran's phosphorous content by feeding it with alfalfa (Lucerne) or other legume (clover) hays or, if feeding grass hay, by adding 2 ounces of feed-grade limestone to the horse's daily grain ration. Dry bran tends to be fluffy, and horses blow it around with their noses. Although it is perfectly fine to feed dry bran, moistening it keeps it from irritating the horse's respiratory tract.