During the coldest months of the year, your horse relies on their slow digestive process to generate enough body heat to keep them warm.
Without access to lush, green pastures, your horse will depend on you to ensure they are getting enough calories to get through the winter. Here’s how you can adjust your horse’s winter diet to help them stay warm and maintain their body condition.

How To Increase Your Horse’s Winter Caloric Intake
Though winter dietary requirements vary between horses, climates, and living situations, on average a horse will need to increase their caloric intake by about 25% during the coldest months. Aim to feed about 1.5 to 3 pounds of quality hay per 100 pounds of body weight.
Horses are designed to spend most of their day eating. Foraging and eating for up to 18 hours a day allows your horse to continuously generate body heat through the digestive process. Free-feeding with a hay feeder can be a great way to ensure your horse has enough to eat and encourage all-day feeding while reducing waste.
A quality hay can help your horse keep weight on in the winter as well as help them produce more body heat through digestion. Monitor your horse’s body condition and if they do not seem to be maintaining weight on hay alone you can supplement with a high fiber grain feed. Adding fats to your horse’s diet is an easy way to supplement calories. < /p>

Keeping Your Horse Hydrated In The Winter
While your horse should always have access to fresh, clean water, staying hydrated is even more critical during the winter months when your horse is unable to graze on moisture-rich grass.
Dehydration in the winter can lead to decreased eating and can put your horse at increased risk for impaction colic. Monitor your horse’s water intake and be on the lookout for dry stools.
You can help your horse stay hydrated in the wintertime by making sure their water trough does not freeze over. At the very least, you should remove ice as it forms. If your horse doesn't like to drink cold water, a heated water bucket can maintain a comfortable drinking temperature.