I use stewing chicken from the supermarket to make soup. I think they are old egg layers, so they are tough as rubber if you try to roast them. However, the reason why they make great soup is because the meat will become edible and won't dry out like roasting chicken, no matter how long its heated.
I find that the key to preparing a retired layer is to keep the water temperature at a bare simmer and never let it actually boil.