Older horses often have a hard time chewing hay properly, which means it doesn't digest properly, which translates to the hay NOT producing body heat for the horse through digestion. Looking at the body condition of the horse from the picture you posted, it would be my personal opinion that this horse would benefit from an insulated waterproof blanket in weather colder than 10ºF due to not having a significant amount of body fat for insulation, especially along the topline.
I have a 32 year old gelding with very few teeth left who wears a medium weight insulated blanket on cold days/nights and it really helps him maintain his body condition because all of his calories are not going into producing heat. The bulk of his diet is senior feed with Empower; he does gum some hay just for something to do, but most of it ends up being spit out in quids. He's had good dental care for the last 20 years that I've owned him, but he's just plain running out of teeth.
Love that picture of your mare SitComGirl!
I have a 32 year old gelding with very few teeth left who wears a medium weight insulated blanket on cold days/nights and it really helps him maintain his body condition because all of his calories are not going into producing heat. The bulk of his diet is senior feed with Empower; he does gum some hay just for something to do, but most of it ends up being spit out in quids. He's had good dental care for the last 20 years that I've owned him, but he's just plain running out of teeth.
Love that picture of your mare SitComGirl!