Remove bags with liver and neck from hens. Wash hens well, pat dry. Rub hens with oil. Prepare marinade. Place hens either in a glass bowl or in 2 plastic bags. Pour marinade over hens. Let hens marinate overnight in refrigerator turning hens or bags over occasionally. Remove hens from marinade. Place on rack in roasting pan. Roast at 450 degrees for 50 to 60 minutes. Cut hens in half lengthwise to serve.