I’m very lucky because I go to Florida in the winters with my horses, so we don’t experience super cold temperatures. But it does get below freezing at home before we head down to Florida. I think it’s important to make sure your horses get enough fresh air in the barn, even when it’s cold outside. I think opening doors and windows, even if it’s just a little bit, is important.
If your horse is coughing, you can try wetting the hay. Getting them outside and making sure there is fresh air in the barn will help too.