Heat the olive oil in a large (12-inch) saute pan and add the pancetta. Cook over medium heat, stirring often, until the fat is rendered and the pancetta is golden brown and crisp, 5 to 10 minutes. Remove the pancetta to a plate lined with a paper towel.
Add the Brussels sprouts, salt, and pepper to the fat in the pan and saute over medium heat for about 5 minutes, until lightly browned. Add the raisins and chicken stock. Lower the heat and cook uncovered, stirring occasionally, until the sprouts are tender when pierced with a knife, about 15 minutes. If the skillet becomes too dry, add a little chicken stock or water. Return the pancetta to the pan, heat through, season to taste, and serve.
Homemade Chicken Stock:
Place the chickens, onions, carrots, celery, parsnips, parsley, thyme, dill, garlic, salt, and peppercorns in a 16 to 20-quart stockpot with 7 quarts of water and bring to a boil. Skim the surface as needed. Simmer uncovered for 4 hours. Strain the entire contents of the pot through a colander, discarding the chicken and vegetables, and chill. Discard the hardened fat, and then pack the broth in quart containers.