Combine the salt, juniper berries, bay leaves, sage, and garlic in a small bowl. Mix together and lightly crumble the bay leaves. Rub on the duck legs and place in a single layer on a baking dish. Cover and place in the refrigerator overnight.

The next day, preheat oven to 225°F (105°C). Wipe off the salt mixture from the duck and pat dry. Place the duck in a dutch oven, but do not stack them. Melt the duck fat and pour until it just covers the duck legs. Cover and bake until the duck is tender, about 3 hours.

Remove from the oven and allow to rest to room temperature. If not cooking that same day, place the duck in an airtight container and cover with duck fat. Can be stored in the refrigerator for up to 3 weeks.

To serve, heat a skillet over medium heat. Place the duck skin side down and cook until the skin is crispy, about 6 minutes. Flip and cook until it is warmed through, another 3 to 5 minutes.