After roasting a chicken, add the chicken bones, scraps, and drippings from the roasting pan into an 8 quart stockpot. Add one chopped onion and enough water to cover the bones, about halfway full.
Bring the contents to a boil then turn the heat down to low and allow to simmer for 4 hours, skimming any foam off the top as needed.
Strain the liquid into a second pot, retaining the bones.
Allow bones to cool then pick out any remaining chicken meat and add back to prepared stock. Discard cleaned bones and boiled onion.
Add spices and salt to taste.
Add the second onion, cauliflower, and carrots and bring pot back to a boil. Turn heat down and simmer for one hour.
Add sweet potato and zucchini and bring pot back to a boil. Turn heat down and simmer one hour more before serving.