Take the duck legs out of the salt and rinse them well. Pack them tightly into a casserole and add enough chicken stock to cover them. bring to a simmer, cover and cook gently for 11/2 hours or until the duck is tender enough to fall off the bone. Lift out the duck, discard the skin and bones and shred the meat while it is warm. cool the liquid left in the pan and then chill it so the fat rises to the surface and sets hard. Lift off the fat.