Step 1 Peel the chestnuts: Heat oven to 450 degrees, cut a deep cross on the flat underside of each chestnut with a paring knife, and roast until the Xs begin to gape, about 15 minutes. Peel off the shells and the tough inner skins. (Chestnuts are easier to peel when they are burning hot; you may wish to roast them in batches.) Bring the stock to boil and simmer the chestnuts in the stock for 20 minutes. Drain chestnuts and reserve stock. Cool completely, then coarsely chop.
Step 2 Meanwhile, melt butter in a large skillet over medium heat. Squeeze the sausages from their casings and fry for five minutes. Stir in the chopped onions and celery, and cook until the onion is soft, about 10 minutes. Pour in the white wine, raise the heat for a minute to reduce slightly, then lower heat to medium and cook for an additional five minutes.
Step 3In the biggest bowl you have, mix together the chopped chestnuts, the dried bread and the sausage-vegetable mixture. Dribble in some but probably not all of the reserved stock — you want the mixture to be moist but not soggy.
Step 4Stuff the bird, or smooth into a greased gratin dish, dot generously with butter, and bake at 350 degrees until crusty and brown, about 45 minutes.