Add chicken to cold water, bring to boil and turn down heat. Add vegetables, simmer, skimming foam as needed. Simmer partially covered for 2 - 6 hours, add pepper corns and garlic last hour. When stock is done strain through a double layer of dampened cheesecloth and refrigerate, covered, over night. Next day carefully skim off fat. Stock will keep for about 3 days refrigerated or about 3 months frozen.