This is much more than a soup; think of it as a fancy New England Boiled Dinner, or a subtly spiced hot pot where everything is cooked together. Prepared with chicken alone, it is called Poule au Pot.
Combine in a very large soup pot:
Bring to a boil, then reduce the heat to low, partially cover, and simmer, skimming occasionally, for 1 ½ hours. Add:
Simmer, partially covered, skimming occasionally, for 30 minutes. Preheat the oven to 200°F. With a slotted spoon, transfer the beef, bones, and chicken to a rimmed baking sheet, tent with foil, and keep warm in the oven. Strain the broth and discard the vegetables. Return the broth to the pot, bring back to a simmer, and add:
Simmer, covered, until the vegetables are tender, 30 to 45 minutes. Discard the herbs and transfer the vegetables to a large platter. For a clearer broth, strain again. Slice the beef and sausages, if using, and arrange with the vegetables on the platter. Skim the fat from the broth and season to taste with:
Ladle the broth into bowls. Pass the meat and vegetable platter after the broth, accompanied with: