Combine the parsley, rosemary, thyme, garlic, oil, vinegar and salt and pepper to taste. Blend together. Place chicken in a glass dish or bowl and pour blended marinade over the chicken. Cover dish and refrigerate to marinate for at least 2 hours or up to 24 hours.
Preheat grill to medium high heat or heat barbecue.
Remove chicken from dish (disposing of leftover marinade) and grill for about 6 to 7 minutes per side, or until chicken is cooked through and no longer pink inside.