I’m going to tag on to this post as I’m in the same situation as the OP … so much rain, and so much mud. The only difference is that the barn isn’t mine, and I realize what’s a bother to ME isn’t necessarily a bother to the person running/affording the place, so I’d be fronting the cost of these myself. Field in question is not only used for my little mare, there are sometimes other boarder’s horses turned out in there too, however, other boarders have left in the past because of the mud.
It’s worse in front of the run-in and by the gate (basically, anywhere I or the horses need to be). Would a small handful of these grids still make a difference, and could I take them with me if I ever moved?