In a stockpot, combine the chicken and neck with the water, onion, carrots, celery, garlic, peppercorns, bay leaf, parsley springs and thyme sprigs and bring to a boil. Cover partially and simmer over low heat for 30 minutes. Transfer the chicken to a plate. Discard the skin. Pull the meat off the bones, cut it into 1/2-inch pieces and refrigerate.