Make your own stock with the bones of the previous chicken you consumed. You then know exactly how much salt is in your stock because you've added it yourself. Put the carcase into a pot with a peeled onion, a couple of chopped carrots and a stalk of celery, cover the lot with water, season, bring to a boil and simmer for a bit. You can add a bouquet garni or whatever herbs you have lying around. Tarragon works well with chicken but is quite overpowering. Check the seasoning partway through cooking. Job's a good 'un.