Combine the sugar and salt.
Place the chicken legs in a roasting pan, sprinkle with salt and sugar mixture, and cure, covered, overnight in the refrigerator.
Preheat the oven to 300°.
In a Dutch oven, combine the stock, the shallots, the thyme, the garlic, and the lemon zest.
Layer in the cured chicken legs.
Cover the Dutch oven and place it in the oven.
Cook for 3 hours, until the chicken legs are very tender.
If storing, pull the meat from the bones, return the meat to the "confit" liquid in the Dutch oven, and toss to combine. Otherwise, serve and enjoy hot.