How to Make It
In a baking dish, rub the chickens with 1/4 cup of the salt. Cover and refrigerate overnight.
In a large pot, combine the remaining 2 1/2 cups of salt and the sugar with 1 gallon of the water and boil, stirring, until the salt and sugar dissolve, 5 minutes. Turn off the heat and add the chiles, bay leaves, garlic, onions, peppercorns, coriander, fennel and star anise. Add the remaining 2 gallons of water, the shanks and the brisket and refrigerate overnight.
Rinse the chickens. Drain the brined meat; discard the garlic, onion and seasonings. Halve the brisket lengthwise along the grain. Divide the chicken, shanks, brisket and sausages between 2 pots. Divide the remaining ingredients between the pots and add enough water to cover the meats. Bring to a boil, then reduce the heat and simmer until the chicken and sausages are cooked through, 1 hour; transfer to a roasting pan and cover loosely with foil.
Continue to simmer the bollito until the shanks and brisket are very tender, 1 hour and 20 minutes. Add the shanks and brisket to the roasting pan. Strain the broth; discard the vegetables and spices. Spoon off the fat. Return all of the meat to the broth to rewarm.
Pull large pieces of meat from the shanks; discard the bones. Thinly slice the brisket across the grain. Cut off the chicken drumsticks, thighs and wings and thickly slice the breast meat. Slice the sausages. Arrange the meats on platters and ladle broth on top to moisten them. Serve the remaining broth with the meats, or reserve for another use.