Barbecue Chicken

6 chicken boneless chicken breasts, trimmed
2 cups ketchup
1/2 cup brown sugar
1/4 cup apple cider vinegar
1/4 cup Worcestershire sauce
1 tablespoon prepared mustard

1. Cut each chicken breast into thirds and place in a 9 X 13 dish.
2. In a large bowl, combine ketchup, sugar, vinegar, Worcestershire sauce, and mustard. 
3. Pour barbecue sauce over chicken.
4. Heat grill to medium heat. 
5. Cook chicken on hot grill, turning once for about 7 to 8 minutes per side or until no longer pink.