Chicken Stock

• 4 pounds chicken carcasses, including necks and backs
• 1 large onion, quartered
• 4 carrots, peeled and cut in 1/2
• 4 ribs celery, cut in 1/2
• 1 leek, white part only, cut in 1/2 lengthwise
• 10 sprigs fresh thyme
• 10 sprigs fresh parsley with stems
• 2 bay leaves
• 8 to 10 peppercorns
• 2 whole cloves garlic, peeled
• 2 gallons cold water