Combine meat, egg, 1/4 cup cooking sherry, juice of lemon (reserve rind), Italian seasoning, salt, and pepper in a medium mixing bowl; mix well. Cover tightly, and refrigerate mixture overnight. Shape into 1/2-inch meatballs, and refrigerate until ready to use.
Remove giblets from hen; reserve for other uses. Remove excess fat from hen; discard. Rinse hen in cold water.
Combine prepared hen, onion, green pepper, celery, barley, remaining cooking sherry, red pepper, garlic, bouillon granules, bay leaf, and reserved lemon rind in a 21-quart stock pot. Add water to cover hen; stir well. Cover and bring to a boil. Reduce heat to medium, and cook 1 hour.
Remove garlic and bay leaf from broth with a slotted spoon, and discard. Remove hen from broth, and cool slightly. Bone hen, and chop meat. Discard bones; return meat to broth. Stir in tomatoes, turnips, and mushrooms. Bring to a boil.
Add reserved meatballs, one at a time, to boiling broth; stir well. Add green beans, corn, peas, carrots, and water chestnuts, stirring well after each addition. Stir in dill weed, parsley, and fettuccine. Cover and remove from heat. Let soup stand 1 hour.
Ladle soup into individual bowls; sprinkle each serving with Parmesan cheese and chopped fresh chives. Serve warm.
Note: Minestrone freezes well.