When I noticed that Grizzly liked the chew toys more than everyone else, I started setting them up in different ways every time I cleaned the cage, to keep him entertained. Soon I tried blocking the pigloos differently each day to give him a little puzzle to solve. He seemed to like it.
I figure, if he can figure out how to unstack things to get through, with enough time and practice he'd be cracking compound locks in no time.