True, it'll have to be a live hopper to start out the scenting, because they will still be relating to motion. Once you get them eating unscented hoppers, it's just a matter of time untill you can get them to eating f/t. The only problem I've seen with racers switching to f/t, is that they like the chase, the hunt that is. So they may need to be fed with a long pair of tongs, or see if they will take one that was dropped and left. Hopefully one of these techniques works for you.