1 medium onion, finely chopped
1 can (6 ounces) tomato paste
1/4 cup reduced-sodium chicken broth
12 tablespoons brown sugar
6 tablespoon cider vinegar
6tablespoon yellow mustard
6tablespoon Worcestershire sauce
6 garlic cloves, minced
5 teaspoons chili powder
3 teaspoon salt
1/8 teaspoon cayenne pepper
8 pounds boneless skinless chicken breasts

1 medium onion, finely chopped 1 can (6 ounces) tomato paste 1/4 cup reduced-sodium chicken broth 12 tablespoons brown sugar 6 tablespoon cider vinegar 6 tablespoon yellow mustard 6 tablespoon Worcestershire sauce 6 garlic cloves, minced 5 teaspoons chili powder 3 teaspoon salt 1/8 teaspoon cayenne pepper 8 pounds boneless skinless chicken breasts

In a small bowl, mix the first 11 ingredients. Place chicken in a 3-qt. slow cooker. Pour sauce over top.
Cook, covered, on low 4-5 hours or until chicken is tender. Remove chicken; cool slightly. Shred meat with two forks. Return to slow cooker; heat through. Serve in buns. Freeze option: Freeze cooled chicken mixture in freezer containers. To use, partially thaw in refrigerator overnight. Heat through in a saucepan, stirring occasionally and adding a little broth if necessary.