In a small bowl, mix the smoked paprika, mustard powder, garlic powder, onion powder, salt and pepper.
Put the pork in a roasting pan and rub with the spice blend. Allow to come to room temperature for 1 hour.
Preheat oven to 300° F/150°C.
Pour the chicken stock into the bottom of the roasting pan. Cover the pan tightly with foil. Roast for 4 hours, or until or the pork pulls apart easily with a fork. If there is a bone, it should pull out very easily.
Remove from the oven and allow to rest for 10 minutes. Skim as much fat off the top of the pan juices as you can, then add 1/2 cup of barbecue sauce and mix.
Shred the meat using 2 forks. Mix until coated in the sauce.
Serve on hamburger buns topped with extra barbecue sauce and coleslaw.