In an 8-quart casserole, heat the olive oil over medium heat. Add the garlic and cook, stirring occasionally, until fragrant, about 3 minutes. Add the sausage and cook, stirring frequently, until the meat is well browned, about 15 minutes. Add the fennel seed and cook stirring for another minute or so.

Place about 1/3 of the chopped onions, 1/3 of the sauerkraut, 1/4 of the thyme leaves, and 1/3 of the kielbasa over the sausage. Moisten with one-third of the stock and a little wine. Repeat twice more, layering onions, sauerkraut, thyme leaves, and kielbasa, then moistening with stock and wine. Arrange the diced pork butt and smoked ham hocks on top of the last layer of sauerkraut, sprinkle with the remaining thyme and the black pepper.

Bring the casserole to a simmer over medium-high heat. Lower the heat and simmer gently for 2 hours, covered, without stirring. Remove the ham hocks. Trim the fat from the hocks then cut the meat from the bones. Return the ham to the casserole. Add the chicken bratwurst and simmer until the bratwurst are fully cooked, about 30 minutes.

When ready to serve, remove the chicken bratwurst. Stir the casserole and add salt, to taste. Spoon the choucroute onto warm plates, top each serving with a bratwurst, and garnish with a thyme sprig. Pass toasted bread, mustard and sour cream as accompaniments.

* Chef's Note: This recipe is even better made with your own sauerkraut recipe! The choucroute can also be served as an accompaniment to game hen or quail. Either bird should be trussed and can stew on top of the choucroute.