Pour vegetable oil into the bottom of a slow cooker. Place the pork roast in the slow cooker, pour in barbeque sauce, apple cider vinegar, and chicken broth. Stir in brown sugar, yellow mustard, Worchestershire sauce, chili pwder, onion, garlic, and thyme.
Cover and cook on high until roast shreds easily with a fork, 5 or 6 hours or more.
Remove the roast from the slow cooker and shred the meat using two forks. Return the shredded pork to the slow cooker and stir the meat into the juices. Let meat cook longer if desired. The longer the better. Spread the inside of both halves of hamburger buns with butter.
Toast the buns, butter side down, in a skillet over medium heat until golden brown. Spoon pork into the toasted buns. Enjoy.