Combine first 9 ingredients in a medium-size skillet; sauté in 1/4 cup butter until tender, and set aside. Place chicken, breast side up, in a 12- x 8- x 2-inch baking dish; brush with 1 tablespoon melted butter. Pour water into baking dish; bake, uncovered, at 375° for 30 minutes or until lightly browned.
Remove from oven, and turn chicken breasts cavity side up. Fill each cavity with about 1/4 cup sautéed oyster mixture. Sprinkle with breadcrumbs, and dot with remaining butter. Return to oven, and bake an additional 20 minutes or until golden brown.