The original question was should this person blanket that particular horse that is on pasture and is a pasture pet, not ridden and just being petted and loved on. It is not being ridden so no need to worry about keeping it with a short hair coat to help dry it out, and no need to exercise it in the winter to keep it in condition. It is just on pasture. So for THAT particular horse I stick by my answer. Let it grow a big hair coat and feed it enough hay. Yes, for any other horse with multitudes of different circumstances, the answer can vary and be complicated. But for this original question, it is not as complicated.