Duck with Sour Sauce: Anatra con Salsa

Name: Duck with Sour Sauce: Anatra con Salsa
Ingredients: 1 (4-pound) duck, cleaned and cut into 8 pieces; 1/8 pound pancetta, finely chopped; 2 tablespoons unsalted butter; 2 sage leaves, finely chopped; 1 branch rosemary; 1/4 pound soppressata, finely chopped; 1 clove garlic, finely chopped; 1/2 cup white wine vinegar; 1/2 cup Brown Chicken Stock, recipe follows; 1 lemon, cut in half; 2 tablespoons extra-virgin olive oil; 3 1/2 pounds chicken wings, backs, and bones; 3 carrots, coarsely chopped; 2 onions, coarsely chopped; 4 ribs celery, coarsely chopped; 2 tablespoons tomato paste; 1 tablespoon black peppercorns; 1 bunch parsley stems