Poach sausage: Place sausage in saucepan with cold water to cover. Bring slowly to boil. Boil for 2 minutes. Remove and peel off skin.
Preheat oven to 350 degrees F. Stuff chicken with sausage and truss with string. Season with salt and pepper. Place in ovenproof dish; add 1/4 cup white wine and butter. Bake 1 hour.
Once roasted, remove string and set chicken aside. Heat pan juices in saucepan over moderate heat. Add grapes. Mix arrowroot with remaining wine and add to juices to thicken. To serve, place chicken on warmed platter and pour sauce on top.