I hardly ever place shoes on my mules. In the summer time, I put shoes on the front hoofs only, if I know the trails will be rocky, or if a hoof has split, I correct it with a shoe. But as a rule of thumb, I seldom put shoes on my mules. Place a mark on your calendar to remind you. Change the brand of worm medication every so often to obtain maximum benefit on the kill of all the different critters your animal can acquire.
Snow build up under the horses hoof is a problem.
Thus the horse can have a difficult time walking. A few things can be done. There is a special plastic plate that can be placed between the shoe and the hoof thus allowing the snow to fall off the hoof. I have used truck tire tube liners. This is the liner on a tire that goes around the wheel for the tube to rest on.