Rich Chicken Stock

4 pounds chicken bones, chopped
3 large yellow onions, quartered
1/2 head celery, coarsely chopped
2 carrots, coarsely chopped
3 Tbsp olive oil
Salt and Freshly ground black pepper
2 bay leaves
1/4 cup whole peppercorns
Small bunch flat leaf parsley, stems only
6 sprigs fresh thyme

Preheat oven to 450 degrees.  Combine chicken bones, onions, celery and carrots in a large roasting pan; toss with oil and season lightly with salt and pepper.  Roast until the bones and vegetables are rich golden brown, about 30-40 minutes.  Transfer the bones and vegetables to a large stockpot, add 48 cups of cold water, and the remaining ingredients and bring to a boil over high heat.  Reduce the heat to medium and simmer for 4 hours, skimming the scum that rises to the top with a ladle every 20 minutes.  Remove from the heat and strain through a mesh strainer into a clean pot.  Let cool to room temperature, cover and refrigerate or freeze until ready to use.

Makes about 16 cups