I like what QtrBel said. That could work. I am wary of putting things on horses' legs. Even what they do in trick training to get the horse to bow or lie down (putting ropes around their legs) gets me nervous. And my old BO used to let her horses run around in the round pen (or elsewhere) with a lead rope trailing around his feet. Made me so nervous.
Anyway, as far as pawing when fed, I wouldn't worry too much about it. If you are worried about the holes or trenches in the ground (I know, they are horribly annoying) try rubber mats like BlueSpark said. I can't wait to try rubber mats once we have our barn built with some real stalls