After roasting or poaching a chicken a la Julia Child, I always complete the process by making chicken stock a la Julia Child! Here is her master recipe for basic meat stock from volume 1 of Mastering the Art of French Cooking.
Place the meat and bones in a stockpot and add cold water to cover them by 2 inches. Set over moderate heat. As the liquid comes slowly to a simmer, scum wills tart to rise. Remove it with a spoon or ladle for 5 minutes or so, until it almost ceases to accumulate.
Add all the ingredients to the left, tying the herbs up in an herb bouquet with cheesecloth. Add more water if the liquid does not cover the ingredients by a full inch. When the liquid is simmering again, skim as necessary. Partially cover the kettle, leaving a space of about 1 inch for steam to escape.Maintain at a very quiet simmer for 4-5 hours. Skim occasionally.
To degrease, set the pot in the refrigerator until the fat has hardened on the surface and can be scraped off.