Blankets are one way to keep your horse warm during the winter, but you can also help your horse generate his own heat by feeding him more forage.
We feed a lot of hay. Much more than my horses ever got at commercial boarding facilities. Long stem forage is good for a horse’s digestion and the digestive process also generates heat. So, the colder it becomes, the more forage you should offer your horse.
According to the North Dakota State University Agricultural Communication,
Cold temperatures also change the daily feeding requirement. The lower critical temperature for horses with a heavy winter coat during dry, calm weather is 30 F. For each 10-degree change below 30 degrees, horses require an additional intake of approximately 2 pounds of feed per day (assuming the feed has an energy density of 1 megacalorie per pound, which is typical for most hay).
A 10- to 15-mph wind will require horses to consume an additional 4 to 8 pounds of hay to meet their increased energy requirements. When a horse without shelter becomes wet and encounters wind, it must consume an additional 10 to 14 pounds of hay.
That’s a lot of hay! One of the ways that I feed hay in the winter is by using soaked hay cubes. I feed 50/50 Timothy Alfalfa cubes, adding 2-3 pounds soaked. Freedom gets his twice a day; Zelda just at dinner. This adds more forage to the diet (without as much volume), cuts down on waste,and also helps keep them hydrated.
Note: while it’s not absolutely essential to soak hay cubes, I always do to prevent the chance of choke.