Stir together cornbread crumbs, stuffing mix, and next 8 ingredients in a large bowl.
Pour cornbread mixture into a lightly greased 5 1/2- or 6-quart slow cooker. Dot with butter. Cook, covered, on LOW 4 hours or until cooked through and set.
Note: For testing purposes only, we used Pepperidge Farm Herb Seasoned Stuffing mix. We also used 2 (7.5-ounce) packages Martha White Yellow Cornbread Mix prepared according to package directions in 8-inch square pans. The baked cornbread made 7 cups crumbs; just freeze the rest.