To make pastry: Combine butter and lard with 2 cups flour and 1/2 teaspoon salt. Add in water and form dough into a ball. Rest in a cool place for 1/2 hour. Roll pastry to 1-inch larger than pie plate: flip pie plate over onto pastry and cut a circle 1-inch wider than the lip. Also cut a 1-inch wide band of pastry to match the size of the overhang. Chill until ready to use.
Preheat oven to 400 degrees F. Remove wings from chicken and cut into 4 pieces, removing backbone and breast bones. Pat chicken pieces dry with towel.
Fry bacon in large pan. Transfer to a dish to cool, then cut into 1-inch dice. Brown both sides of chicken pieces in bacon fat over high heat. Season with salt, pepper, allspice, and paprika. Transfer chicken to pie pan.
Add 1 tablespoon flour to bacon fat to form a roux and then add dry and sweet sherry, stirring until smooth. Pour this over chicken. Place 1/2 sage leaf on each chicken piece. Surround with grapes and sprinkle grapes with brown sugar. Cover chicken with bacon.
Dampen edge of pie plate with water and attach band of pastry, pressing down with fingers, so it sticks out from the edge. Dampen the surface of the pastry band with water and attach pastry circle to it, crimping to seal. Cut a steam vent in top of pastry. Brush crust with egg yolk and bake for 30 minutes.