Project Kong Chewing

I love Kong toys and so do my dogs, but I feel like they are missing out. At this point we have maybe ten of them that I keep in the freezer, stuffed full of peanut butter and other tasty things. While all three dogs thoroughly enjoy licking peanut butter out of a Kong, none of them are very good at unstuffing the toys.
Kong's durable rubber chew toys are designed to be stuffed with biscuits, kibble, and squishy things like peanut butter. The dog can lick these goodies out of the toy, but sometimes the food gets stuck in there. Chomping down hard on the small end of the toy is the traditional move from the Kong playbook for loosening up trapped cookies. None of my dogs appear to know that maneuver, so I am attempting to teach them.

As of now, all three dogs see Kongs as food dishes rather than playthings. Once emptied, the toys lose all interest. Brisbane is not a recreational chewer, they doesn't enjoy gnawing on non-edible toys just for fun. Ulysses is also largely uninterested in gnawing non-food, with the exception of a ball during a game of fetch. Ru loves to chew his Nylabones, and also the occasional dropped wine cork.

The plan so far:

1. Play with the Kongs. This seems really obvious, but the Kong toys spend the vast majority of their time in the freezer, and are rarely on the floor and available for the dogs to play with. Since they are associated with food they could potentially become a source of conflict for Brisbane and Uly. I am addressing these issues by bringing unstuffed Kongs out for individual playtime in the yard. The dogs get to enjoy that unpredictable bouncing feature, and we both get some well-deserved one-on-one time together.

2. Size down. Since I'm trying to introduce the dogs to the concept that Kongs are made of rubber and can be chomped, I want to make things as easy as possible. Both Ulysses and Brisbane fall squarely into the large Kong's 30-65-pound range at 50 and 40 pounds, respectively. The large toy is definitely not a choking hazard, but the small end is still a bit of a stretch to get their back chomping teeth around. I'm comfortable letting them chase and chomp a medium size Kong with supervision.

3. Power down. The black Kongs are the hardest, least flexible, and most durable. The royal blue Kongs are less durable and more flexible while still being tougher than the classic red Kongs. Even softer than that are the purple senior Kongs, and the softest are the pastel blue and pink puppy Kongs. I don't like to admit it, but Brisbane can probably be considered a senior dog now. My vet thinks Uly is around eight years old, and his teeth are very worn, so he also fits the description of senior. I recently acquired (and then ruined) a senior Kong, but I thought I'd go even squishier and try out a baby Kong. (Yes, this is against manufacturer recommendations, and yes, it is potentially risky, however neither of the big boys chews on stuff for fun or tears things up or eats things that aren't food.)

So far, just bouncing a small Kong around the yard convinced Ru that this toy is good for gnawing. Hopefully this improves his toy-emptying performance. Will chasing and fetching a medium-size puppy Kong be enough to get Uly and Briz chewing instead of just licking?