In a Dutch oven, cook bacon over medium heat until crisp. Remove to paper towels to drain; set aside. Add butter to the drippings (you can spoon out some of the drippings if you don’t want to use that much); saute celery, leek, and onion until tender. Add garlic; cook 1 minute longer. Stir in the potatoes, broth, clam juice, salt, pepper and thyme. Bring to a boil. Reduce heat; simmer, uncovered, for 15-20 minutes or until potatoes are tender.
In a small bowl, combine flour and 1 cup half-and-half until smooth. Gradually stir into the soup. Bring to a boil; cook and stir for 1-2 minutes or until thickened.
Stir in (drained) clams, shrimp, crabmeat, and remaining 3 cups of half-and-half; heat through (do not boil); turn down to low heat; add the bay leaf. Cook for additional 2-3 minutes on low heat. Add in 4 strips of crumbled bacon, and season to taste with Old Bay seasoning.
Crumble the reserved 2 strips of bacon. Garnish chowder with crumbled bacon and fresh chopped chives.