In a mixing bowl, stir together the pork shoulder and pancetta with your hands until well-mixed. Add pepper, salt, fennel seeds, and white wine and mix until well-blended, again with your hands. Work quickly so that body temperature does not change the texture of the fat. Set up the sausage stuffer and place the casing over the funnel feeder. If you do not have a sausage stuffer, form the sausage into 1/4-pound logs, by hand, and be careful handling them. Stuff the sausage into the casings, twisting every 3 1/2 to 4 inches so that each sausage is about 4 ounces, and form 22 to 25 sausages. Prick them all over with a needle and divide into four equal batches.
Preheat the oven to 400 degrees F.
Place each batch of sausage in a single layer in the center of each piece of parchment and fold in half like a book. Divide the scallions and favas among four packs, place 1 hot chili on top of each and drizzle each with 2 tablespoons oil. Fold so there are no openings, seal the edges of each packet with the egg whites and place each packet on a sheet tray. Cook in a pizza oven 30 minutes, remove. Cut the bag with scissors at the table and sprinkle with the herbs. Serve in the bag.