Stir together onion, celery, bread, pepper, parsley, sage, rosemary, thyme, and celery salt in a large bowl; pour melted butter over bread mixture and stir to combine.
Spoon stuffing into the cavities of chicken; place chicken into a roasting pan. Sprinkle chicken with savory; cover with a lid or foil.
Bake in the preheated oven for 1 hour. Remove cover; increase oven temperature to 425 degrees F (220 degrees C). Roast until browned and an instant-read thermometer inserted into the thickest part of the thigh, near the bone, reads 165 degrees F (74 degrees C), about 15 minutes.