Preheat oven to 375 degrees F. Lightly grease a 9x13-inch baking dish; set aside.
Crumble the cornbread into a large bow; set aside.
In a large skillet over medium heat, cook the sausage, breaking it apart as it cooks, until completely browned. Remove the sausage with a slotted spoon to a paper towel-lined plate.
In the same skillet, add the onion, celery and apple, and cook over medium heat until the onion is translucent and the celery and apple are softened, about 5 to 8 minutes. Remove from the heat.
Add the sausage and cooked onion mixture to the bowl with the cornbread and stir to combine. Add the poultry seasoning, salt and pepper and stir to thoroughly combine. Add 2 cups of the chicken broth and stir until the mixture is evenly moistened. If it still seems a bit dry, add more broth a little at a time until the mixture appears damp.
Transfer the stuffing to the prepared baking dish, pressing it into an even layer. Drizzle with the melted butter and bake until the top is golden brown, 35 to 45 minutes. Leftover stuffing can be stored in an airtight container in the refrigerator for 3 to 4 days.