If it is still small, I could see a breeder feeding a couple of frozen thawed, then selling. Sometimes they aren't exactly extablished for the long term and live items may need to be offered a few more times. Feeding live pinks that still wriggle a bit will not hurt them. Their main concern is getting the prey consumed before it gets away. Obviously, larger animals will put up a fight and the snakes usually key in on what animals are going to put up a fight.
I would say if his feeding response continues to be positive, you could try f/t again after 6-10 more feedings. Usually once they hit the fuzzy stage they are good to go. I'm glad to hear he's doing well for you now. Good luck and keep up the good work.