Rub salt and pepper into the skin of a whole chicken.
Place one peeled, cored, and quartered apple and one stalk chopped celery (or use some dried celery leaves if you don't have a stalk of celery) inside the chicken.
Place chicken in a slow cooker.
Sprinkle one chopped onion, ½ teaspoon crushed, dried rosemary, and juice and zest of one lemon over chicken.
Pour 1 cup hot water into the slow cooker.
Cover, and cook on High for 1 hour. Switch to Low, and cook for 6 to 8 hours, basting several times.
