Put chicken and broth in crockpot and cook on low for 4-6 hours.
Remove chicken and drain all liquid. With two forks shred the chicken.
Place the chicken back into the slow cooker and pour the dressing, Parmesan cheese, parsley, and pepper over the top. Stir until chicken is coated well.
Cook for another 30 minutes or until heated through. Spoon mixture into buns and top with romaine lettuce and extra parmesan cheese if desired.