Rinse chicken under cold water. Dry with paper towels. Preheat oven to 350 degrees F.
Make stuffing: In large bowl, using a spoon or portable electric mixer, beat yams with ¼ cup butter (or margarine) until light and fluffy. Add rest of stuffing ingredients, except remaining butter, and toss lightly with fork until thoroughly mixed. Lightly fill neck and body cavities of chicken with stuffing.
Do not pack stuffing, bake any leftover stuffing mix in a shallow pan along with chicken during last 30 minutes of roasting. Truss chicken : Bring skin over neck opening and pin to back with poultry pins. Close body cavity with poultry pins.
Pin wings to body; tie legs together with twine. Place chicken, breast side up, on rack in shallow, open roasting pan. Cover with cheesecloth dipped in ¼ cup melted butter.
Roast uncovered for 2½ hours at 350 degrees F. Remove cheesecloth and brush bird with rest of melted butter. Roast uncovered for another 50-60 minutes.
Remove bird to warm platter; remove pins and twine. Keep warm. Make gravy, Pour fat drippings from roasting pan into bowl. Measure tablespoons of drippings and return to roasting pan.
Stir in flour to make a smooth mixture. Place roasting pan on top of stove over low heat and gradually stir in canned chicken broth--stirring continuously until smooth and mixture comes to a boil.
Add rest of gravy ingredients. Simmer for another minute or so, stirring constantly. Serve gravy hot, with chicken and stuffing.