Never found any product applied to hooves that actually works more than 15 minutes. Spray shortening, lard, wax, all have a VERY short no-stick ability.
Something I have noticed is that barefoot horses moving briskly, throw out packed snow in hooves. We used to pull each other on skis at a canter, not the least bit of slipping. Unridden horses being snorty in the paddock, trotting with heads and tails up, also throw snowballs out. They have snappy leg, ankle action to fling the snowballs. It is the slower movers, walking, being tentative, which let the snow build up in hooves, so then horses moves even more tentatively.
Snowballs melt off if stalled overnight or you can chunk them out. I have a snowball hammer, like teamsters used on horses in the old days. It has a single long claw behind to use hitting snowballs to break them apart. Looks scary, but I pull my hits, snow ball is pretty hard, so I don’t actually hit any part of hoof with hammer. But for me, this is the BEST tool to clean out icy hooves. I have tried lots of other methods, tools over the years, but they were a lot more work with poor results.
You can Google Snowball Hammer to get a picture, see how the design can work for you. A blacksmith made mine, but there are antiques out there too. Not sure anyone makes them these days.