After seeing a horse at the barn up north I was working fall on the ice because he didnt have winter shoes I would never leave a horse without winter shoes. The worst part was I had 4 horsess with me and had to stick them in the pasture before helping him. Very scary experience.
Several years ago we had an older, barefoot mare fall on ice and break her hip. It was a horrible experience, even barefoot horses can't stay up on ice and now we make sure that the horses stay in if black ice forms.