While duck is poultry, flavor-wise it is miles apart from a standard chicken or turkey. Duck has more fat that the more common poultry and the skin of the duck can be rendered to be very crisp. When preparing just duck legs, a Dutch oven lets you poach them in the oven. This is usually done in rendered duck fat, but a vegetable-based oil or shortening can work as well.
Pat the duck legs with paper towel and coat the duck legs, both under the skin and on top, with seasonings; good choices include dried thyme, dried rosemary, minced garlic, salt, and ground black pepper. Place the duck legs in a sealed container or resealable plastic bag. Keep the duck legs in the refrigerator at least overnight and up to 48 hours.
Preheat the oven to 200 degrees Fahrenheit. Shake off any excess seasonings from the duck legs. Place the duck legs in the Dutch oven with the skin side down. Add the rendered fat or vegetable oil to the pan, enough to cover the legs. Heat the Dutch oven on medium-high heat for 5 minutes until the fat begins to bubble.
Place the Dutch oven into the oven and cook for up to 5 hours. Insert an instant-read thermometer into the thickest duck leg. You should see that the juices run clear from the leg, not tinged in pink with blood, and that the meat registers at least 165 F.
Remove the pan from the oven and remove the duck legs from the fat. Wipe away any excess fat. Heat a large skillet on medium high heat. Add the duck legs, in batches if necessary, to the skillet with the skin side down. Cook for 5 minutes until the skin becomes crispy.
Drain the duck legs on paper towel and allow to rest for 5 minutes before serving.