At least 4 hours before cooking: Roll each chicken breast (small end to large end), wrap with bacon slice and secure with toothpick or bamboo spear. Place rolled chicken breasts into a shallow glass container and add salad dressing to marinate. Cover and put in refrigerator for 2 hours, turning occasionally.
Lightly oil grill and preheat to high.
Remove chicken rolls from marinade and grill over hot coals until bacon browns; move to cooler spot on grill and cook another 25 minutes or until chicken juices run clear. Baste with barbecue sauce, turning and basting for another 10 minutes or until ready to serve.