Exercise can be continued and horses should get as much free exercise as possible. Dr. Scoggins asserts that once the horse is through working for the day, to make sure that the hair is fluffed up before turning them out. The hair coat is sufficient as long as they are dry and not in the wind. If clipped, they will need a turn-out rug. Hoof care must be followed through on a regular basis.
Frozen ground can cause hoof breakage and can get slick.
Turning a horse out where there is sand or some mixture on the ground can help prevent injuries. Most importantly, do not turn the horse out if it is very slippery. Most of the parasites we deal with in the Midwest can survive well in the winter and even thrive if the winter is mild. Horses are very susceptible to respiratory disease and can be affected by the ammonia that is produced from urine breakdown. A three sided shed facing south or east with a good wind break is more than adequate to house your horse over the winter.