Clean the chicken and truss the legs and wings close to the body. Sprinkle the bird inside and out with salt and pepper, and in the cavity put 6 tablespoons butter creamed with 1/4 tsp each of chervil, chives, and tarragon, all finely chopped, and freshly ground pepper to taste. Lay the chicken on its side in a roasting pan and rub chicken with soft butter. Roast the bird in a hot oven (400° F) for 20 minutes. Turn it on its other side, rub with more soft butter, and roast chicken, turning and basting chicken frequently with the pan juices, for about 1 hour, or until chicken is golden brown and tender. Put the chicken on a heated platter, pour the pan juices over chicken and garnish with chopped watercress. Recipe makes 4 servings of Herb Roasted Chicken.