Arrange clams in a large Dutch oven. Cover and cook over medium-high heat 8 to 13 minutes, until clams open. (Clams will release broth while cooking.) Transfer clams with slotted spoon to a large bowl; set aside. Discard any unopened clams. Strain broth from clams into a 1-quart glass measure; add chicken broth and enough water to equal 4 cups. Transfer to a medium saucepan; set aside.

When cool enough to handle, remove clams from shells. Chop clams and return to large bowl; discard shells.

Bring tomatoes and juice, fennel and onion to boil in a Dutch oven. Cover and cook over medium heat 7 to 9 minutes, until vegetables are tender; transfer to bowl with clams. Increase heat to medium-high; add butter and red pepper flakes; cook 1 minute. Add shrimp in a single layer; cook, turning once, 2 minutes, just until opaque. Add garlic; cook 1 minute more. Transfer to bowl with vegetables. Add wine, rice and thyme to pot; cook just until liquid is absorbed. Stir in 1 cup of the broth mixture; cook, stirring, until liquid is just absorbed. Add remaining broth mixture, 1/2 cup at a time, stirring until liquid is absorbed each time. Cook 20 to 25 minutes more, until rice is tender. Stir in shrimp, clams and vegetables and parsley; heat through. Serve immediately. Makes 4 servings.