We always called those skids.
When you take the blade off for the summer, you might want to put it on some blocks so it isn’t sitting on the ground. Less potential for rusting that way. Or you may want to store it somewhere such as the barn you mentioned.
Actually, Western Plow calls the ‘Shoes’. I just ordered some. :shrug:
Skids is probably a better description.
Blocking the plow up is a good idea for storage. What really helps is to get the arms that attach to the truck blocked up at the correct level so that when you re-attach it, you can ‘just’ drive into it.