It is important to feed on a regular schedule to allow the horse to have regular and consistent opportunities to eat. Because the horse evolved as a grazing animal, its digestive tract is designed for small frequent feedings. Missing an evening meal can mean just the concentrate part of the meal, or it could mean the horse missed everything including the forage/hay part as well. If it is the concentrate part and the choice is feed grain later than normal, i.e., many hours later, we would let the horse miss that meal and feed the next morning starting with some hay to make sure the horse does not overeat when it receives its grain meal. If the horse missed the entire feeding, again start with some hay to reduce how hungry the horse is before you feed the grain part of its meal. Sometimes the schedules we keep may affect how we feed our horses, but missing the odd grain meal should not be a major concern. You will need to watch how you feed the day after the missed meal as a hungry horse may eat too fast, and this can cause digestive upsets.