Meanwhile, cut the turkey neck and gizzard in half. Heat the vegetable oil in a medium saucepan and add the neck, gizzard, heart and wing tips. Cook over moderately high heat, stirring occasionally, until browned and crisp, about 7 minutes. Stir in the onion and celery and cook until golden. Add the wine and boil until reduced by half, about 7 minutes. Add the chicken broth and bring to a boil. Stir in the tomatoes, parsley, thyme and bay leaf and cook over very low heat until reduced to 3 1/2 cups, about 1 hour. Strain the turkey stock into a bowl; reserve 1 1/2 cups for the stuffing.