Place sausage, celery and onions in a large, deep skillet. Cook over medium high heat until evenly brown. Drain, crumble and set aside.
In a large bowl combine sausage mixture with cornbread, bread crumbs, chicken broth, poultry seasoning and sage. Mix well and transfer to a 9×12 inch baking dish.
Bake, covered, for 45 minutes or until well set and cooked through.