In a large stockpot add all leftover turkey bones and cover with water. Bring to a boil then simmer for 4 to 8 hours. When complete, strain turkey broth and throw away the bones. If you don't have enough for the broth in the soup you can use chicken broth.
In a large stockpot or dutch oven over medium-high heat add chopped bacon and render for about 3 minutes. If you don't have enough bacon fat to cook the onion, add about a tablespoon of butter. Add onion and cook until translucent, about 5 minutes. Add garlic and cook for an additional minute. Add flour and thyme and stir for about 30 seconds until incorporated. Add broth and potatoes, when it comes to a boil reduce to a simmer and cook for about 30 minutes until potatoes are tender.
Add turkey, half-and-half, salt and pepper and cook until heated through for about 15 minutes. Serve and top with green onions and freshly ground pepper.