Remove giblets and neck from turkey; set aside. Rinse turkey thoroughly with cold water. Place turkey, breast side up, in a deep roasting pan. Insert meat thermometer in breast or meaty part of thigh, making sure it does not touch bone. Place giblets and neck, celery, onion, bay leaf, 1 teaspoon salt, and red pepper around turkey; add 2 quarts water.
Cover and bake at 325° for 3 hours or until meat thermometer registers 185°, basting occasionally with pan drippings.
Remove turkey from cooking liquid; set aside to cool. Remove turkey from bones; cut into bite size pieces. Cover and refrigerate overnight.
Strain cooking liquid, reserving broth; discard vegetables. Cool broth to room temperature; cover and refrigerate overnight. Lift fat from top of broth; discard fat.
Melt butter in a large Dutch oven over low heat; add flour, and stir until smooth. Cook 1 minute, stirring constantly. Gradually add 6 cups turkey broth; cook over medium heat, stirring constantly, until thickened and bubbly. Stir in Worcestershire sauce, if desired, 1/2 teaspoon salt, white pepper, and turkey. Cook over low heat, stirring occasionally, until thoroughly heated. Spoon hash into a shallow serving dish. Garnish with parsley sprigs and pimiento strips. Serve hash over hot biscuits or waffles.