What's the difference between play and work? To me, work is something that you have to do but don't really want to, whereas play is something that you do because it's fun for you and you'd pretty much choose to do it anytime.
I train service dogs. These dogs have to be ready to perform their service behaviors at all times. Their owners see the dogs as "working dogs" - but the dogs see it as play. They enjoy doing what they do because they get rewards for it. One reason that our service dogs could fail out of the program is because they don't enjoy training, they don't enjoy working.
I honestly don't know how you'd go about teaching a dog to shed hunt (or to do anything) as if he were working, instead of teaching it like a game.