I would NOT do a large processed bone... a power-chewing dog can easily cause slab fractures of the molar teeth with these. You can get all manner of squishy-gooshy stuff... canned dog food, yoghurt mashed with banana, canned pumpkin and ground meat, etc. depending on what your dog likes... mix with some kibble, pack the Kong with the mixture, stick it in the freezer overnight, and give it like that. Your dog has to thaw and extract whatever you've frozen in there, and it is a pretty long-term project. I don't know what they are called, but there are basketball sized hard plastic balls that some dogs like to play soccer with. They have a recessed plug that you can remove to add whatever you want for sound effects (a handful of rice or marbles or whatever). The ball is too large to be gripped with the mouth, and is therefore indestructible. Some dogs "get" playing with these... other dogs don't. Possibly a large, whole, RAW steer femur, but it depends on your dog. I would only give this if there are short periods of confinement (an hour or two) that he can have it for. If he is bored, he may do nothing but gnaw on the bone... he will have tooth wear and consume too much of the bone at a time. Not sure where you are posting from, but if the weather will allow, put a sturdy kiddie pool in his pen. This depends on your dog, too: some dogs destroy stuff and some dogs destroy and consume stuff. If your dog does not consume stuff, you can leave him a huge cardboard box to shred every day (make sure it has no staples!). A friend of mine did this with her Rottweilers, and came home to piles of tiny cardboard confetti everyday... I tried this, and my Dobermans ate the box LOL!