My first pony was a chronic cribber. I tried everything! I sprayed everything I could think of on the stall but nothing worked. His original owners used a cribbing collar but he managed to crib anyway. He had freechoice hay and plenty of mineral. I also tried stall toys (boredom busters). He was 11 when I got him and he had been cribbing his whole life. And he crib until the day he died, he once cribbed on my finger!!
Don't mean to discourage you, lol, but those are all the things I tried in the 6 years I had him.