Step 1Bring a saucepan of water to a boil. Blanch the pig's foot for 10 minutes, skimming to remove scum. Drain and reserve.
Step 2Cut 1 onion in half, place it on a baking sheet and char it under the broiler.
Step 3Add the charred onion to a very large stockpot along with the blanched pig's foot, the short ribs, brisket, 1 1/2 gallons of water, bouquet garni and salt.
Step 4Slowly bring to a boil, skimming thoroughly, then reduce the heat and simmer 10 minutes. Cover the pot, leaving a small gap, and continue at a low simmer for 1 1/2 hours, skimming every so often.
Step 5Add the chicken and continue at a low simmer until the chicken and beef are very tender, 45 minutes to 1 hour.
Step 6Add the remaining onions, the carrots, turnips, leeks, potatoes and cabbage to the pot and simmer over low heat 20 minutes or until the vegetables are tender.
Step 7Use a large slotted spoon to remove the meat and vegetables to several large baking dishes. Pour a few cups of broth over the meat and vegetables and tent with foil or cool and refrigerate overnight.
Step 8Strain and defat the remaining poaching liquid. Discard the pig's foot. Pour the stock into two wide sauce pans and reduce by one-third. Cool and refrigerate if serving the next day. Season with salt and pepper to taste.
Step 9To serve, slice the brisket. Place the sliced beef and ribs on one side of a large platter, the chicken in the middle and the vegetables on the other side. Pour some of the reduced broth over all. Serve remaining broth on the side. Put the garnishes in little ramekins and serve alongside the platter to be added as desired to each serving.