Remove the skin from the chicken and cut off the legs. Place the chicken and the chopped onions in a large pot and add just enough water to where the chicken is barely covered by the water. Add 1 teaspoon of salt to the water and bring it to a boil. After about 10-15 minutes of boiling, some froth should start to surface on the broth. Skim the froth off the top and discard it. Do this every 5-10 minutes of boiling. Boil the bird for an hour, or until it is cooked through. Preheat the oven to broil.
Meanwhile, measure out 6 cups of the chicken stock and place it in a medium-sized pot (any remaining excess stock in addition to this 6 cups can be placed in an airtight container and frozen for up to 1 year). Add 2 cups of water to the 6 cups of stock and another teaspoon of salt and bring back up to a boil again. Add 3/4 cup orzo noodles or rice and boil until they're cooked all the way through, then remove the pot from heat and set aside.