In a natural, free roaming situation horses graze nearly constantly throughout the day and night. When feeding horses in stables it is ideal to try and mimic this feeding behaviour.
Horses in stabled conditions should be fed their grain concentrate over at least 2 meals per day and hay should be provided to they can pick at it continuously between feedings. Horses in strenuous training will likely need to be fed 3 to 4 times per day to safely consume enough concentrate to sustain their increase workload.
If roughage is not offered continuously throughout the day it can increase the horses risk for gastric ulcers.