Put all the ingredients into a large pot. Cover with water and cook over high heat until the water comes to a boil.
Reduce heat to low, cover and simmer for 2 hours, stirring every now and then. A greyish foam will float to the top as the stock cooks, skim this off as it cooks
Strain through a fine sieve and discard the solids. Pour into an airtight container and refrigerate overnight.
The next day, remove the top layer of fat that has solidified. Discard.
Store the chicken stock in an airtight container in the refrigerator for 5 days or freeze for up to 6 months. If freezing, you may want to separate into smaller containers.