I emptied out my freezer just recently and had the remains of two full pork butts and maybe 2-3 pounds of already shredded pork butt. I have one of those self-defrosting freezers, so it wasn't pretty. As careful as I was in the wrapping of the meat, ice crystals had still built up and to me this was freezer burn.
What to do? "Dog Jerky". The already pulled pork was a lost cause but my dogs loved it over several days of feeding.
A cooked and defrosted pork butt doesn't shred while cold, so I sliced mine very thin and the grain is weird so all you can do is keep turning it to try to grab the best slices. You'll end up with a lot of small bits and pieces but that's the cooks reward. Feast on those tidbits later while you're bagging up your treats.
Cut the slices into jerky sized pieces and toss every morsel of meat into a pan of your favorite marinade overnight. Put it all, meat and pan, in the meat dryer the next day and let it do it's thing.
Let me tell you. People, dogs and cats will fight over who has the right to chew these tasty treats.