Place the duck legs in a large saucepan, then fully cover with water. Stir in the duck or chicken stock and add the bay leaves and Herbes de Provence. Add 15 ml (1 tbsp) of sea salt and season generously with pepper. Cover and bring to a boil.
Reduce heat to low and simmer for 90 minutes.
Remove the duck legs from the saucepan and let cool on a large plate. Add remaining ingredients to the saucepan, except the diced sweet potatoes and corn kernels, and mix.
Simmer for 25 minutes over medium-low heat.
In the meantime, debone the duck legs and tear meat into large chunks, and add to the saucepan.
After 25 minutes of cooking, add the sweet potato cubes to the saucepan and continue cooking for 15 minutes.
Add corn and cover. Turn off the heat and adjust seasoning. Let stand for 15 minutes before serving with slices of farmhouse loaf.