Just my opinion but I
believe that blanketing a healthy unclipped horse in the winter just
makes US feel good and is no real favor to the horse. I too think it
just messes with what they do naturally all on their own. I don't clip
or blanket and never have in the 28 years I've had horses/mules. I have
most always let mine have run-in access 24/7 and never had a problem.
Never had to up the feed all that much. Even when it is raining and
they get went and it is cold and the hair looks all packed down. I've
never seen them have a problem and they were the ones that chose to
stand out and get wet.
Now when I got my mule early last spring and brought her from Southern
Illinois to Maine, she had shed out a lot and she was cold and
shivering here. So I absolutely did blanket her until things warmed up.
And ..... I ride in rain pants. They have worked great.