Every week I make homemade chicken stock in my slow cooker, with the carcass of a rotisserie chicken or a chicken I've roasted at home.
It couldn't be easier: toss what's left of the chicken carcass into a four-quart slow cooker; add one onion, cut in half, skin and all; add one stalk of celery, with the leaves, and one carrot, cut in half; add a bay leaf and half a dozen peppercorns, and water. Set the cooker on high for three hours, or on low for six hours. Walk away, read a book, check your email, take a nap.
Strain the stock into a freezer-safe container, and let it cool to room temperature on the counter top. Then, store for up to one week in the refrigerator or six months in the freezer, and make soup to your heart's content.