traditional chicken soup, or medicine soup as my lot call it really needs raw chicken with a bone, so whole chicken/thighs/drumsticks
My recipe is
Onion, don't peel, cut into quarters
Carrot, big fat one, or a couple of small ones, again don't peel, snap into bits
Celery stick...even if you don't like it, JUST DO IT!
Big bunch of parsley ....cut off leaves and keep, only put stalks in now
Couple of garlic cloves, again don't peel
Chicken with bones in!
Put all of this into a biggish pan, veg under chicken, cover the lot with cold water, add a good amount of salt and some peppercorns, bring it to the boil with the lid on, turn it down to a bare simmer and give it about 40 minutes
Turn off heat and leave it alone until cool enough to handle
Strain the stock into a bowl, cover and fridge overnight, in the morning the fat will be layered on top and can easily be removed, and the stock should be jellied.
Strip all the meat off the bones and again keep in fridge overnight
To complete the soup, start with some finely sliced onions and celery and sweat until really soft, (keep a little of the chicken fat for this if you remember) then add in the stock, the chopped parsley leaves and as much of the chicken as you like. Add in some snapped spaghetti and simmer gently until the pasta is soft.
You probably will need more S&P. Chicken soup seems to need inordinate amounts of salt!
If you don't want to fridge it all overnight you can leave that out, and just go for it as soon as you have the chicken stripped off, and skim off any excess fat with kitchen roll as you simmer it the second time.
You can make chicken stock in the same way with a carcass from a roast, but it's never quite the same. To complete the soup, add in any leftover chicken once the stock is done and reheat to piping hot.