You said you went to gritty dogs and that hasn't worked. What were you running before? If gritty/rough isn't getting it done, try going the opposite direction...loose dogs. Its amazing how hogs started to bay up for us this summer when we went from 4-5 dogs to 2-3 loose dogs. The hog kinda thinks he's winning when 2-3 dogs are backing at him but won't get close enough to bite. Put one dog in the mix that gets up on him and tries to pull hair.....its off the races. It might not work in some situtations but its worth a try.
Cull Buck makes a great point, when the ruff dogs are busting bays go to a couple of stand-off kind of dogs and you might see a difference