Before modern times, Horse Blankets were always wool or cotton, providing very little variation in the degrees of insulation. In the current era, it’s easier to buy different kinds of horse blankets that provide different amounts of insulation. Some kinds of blankets are more resistant to the elements, with inner and outer layers with insulation in between. The outer lining in a modern horse blanket is generally waterproof and more windproof, while the inner layer won’t flatten a horses coat (less chance of overheating) or chafe. Also, always make sure that you have the right fit for your horse. Too tight can cause injuries and chafing, while too loose will slide off your horse.