You can make stock from raw chicken bones, cooked chicken carcasses, or a combination of both. Add vegetables such as celery, onion, carrots and herbs to the pot, then cover with water. Add salt and pepper to taste, then bring to the boil and reduce immediately to a simmer, allowing the stock to simmer for about 4 hours. Remove the bones and vegetables with a slotted spoon then strain the stock through a fine sieve. Chicken stock can be boiled rapidly for another hour to further reduce and intensify the flavour if you like. Store in airtight containers in the fridge for up to a week, or up to 3 months in the freezer.