Chop the chicken carcass into about 2-3 inch pieces.
In a large stock pot, heat a splash of olive oil, then add the carcass pieces, neck, feet, cook to just brown them, this brings out some flavor.
When the carcass pieces are browned, add some celery, carrot, onion to the pot as well as a some black peppercorns, and a pinch of salt. Add water to the pot to cover the chicken and vegetables by about 2 inches. Set to a simmer.
Simmer for 4-6 hours, skimming off any foam at the top. Add water as needed to keep it above the chicken.
Remove the bones and vegetable pieces and discard, and pour this through a strainer lined with cheesecloth to remove any solids.
Pour the liquid into jars, let cool to room temp, and you can store this for up to 3 days. Use as needed in other recipes.