Horses should be kept within the desired BCS range throughout winter. They must be fed and managed to increase their BCS to an acceptable level before cold weather. One BCS unit can be added to a horse in 30-45 days. When cold and damp, it is more difficult to get horses in proper body condition, as more feed is needed to keep them warm and less energy is available to be stored as reserve body fat. Older horses or any horse with a chewing problem should have its teeth checked before starting to eat coarse feeds such as hay.
Horses can withstand cold weather rather well if dry, in good body condition and adequately fed.
A horse with a slight layer of fat under its skin will be warmer than one that has no body fat. A high 5-6 BCS indicates some body fat covering. Properly feeding hay also will aid in keeping horses warm. Horses are most severely affected when it's wet and windy. Long, dry, winter hair captures body heat produced by the horse and helps insulate against the cold.