I would try to cut back on the grain, and add soak beet pulp into her diet. And I'd recommend a Omega-3 fatty acid supplement to her diet. That will help with skin/coat issues and get a really good shine for the show ring.
Obviously, the best thing to do is get a better quality hay into her diet, or better pasture, but I completely understand how that is probably impossible unless you move her someplace else.
Is she on a regular deworming schedule and her teeth are in good shape?
"The greatest pleasure of a dog is that you may make a fool of yourself with
him and not only will he not scold you, but he will make a fool of himself too."