No matter how you roast a chicken, there’s always a next step: Broth. Break up the bones that are left, and put them in a slow-cooker or a stock pot. Cover them with water. If you’re cooking in a stock pot, simmer about 3 hours, until it tastes good. If you’re using a slow-cooker, cook it overnight. Then remove the bones and throw them away – all their flavor is in the broth. If you have some onion or carrot lying around when you’re putting the broth on you can chop them and throw them in. Perhaps some herb stems or spices. But, personally, at home I usually just use water. Then I add the vegetables after the chicken broth is finished. It’s quicker and easier, and you get the flavor of the vegetables from the second cooking.
Then, you can do whatever you want. Usually I add some vegetables (onion, carrot, squash, tomatoes, whatever I have on hand) and grains or beans, and cook with salt until everything is tender. It makes a great soup.