Preheat oven to 500F (260C).  In a large roasting pan add beef soup bones and chopped vegetables. Place in oven and bake for 20 minutes or until the bones and veggies are beginning to brown.  Remove from oven and place bones and vegetables in a very large stock pot. Add enough cold water to barely cover bones. Set aside.

Place the roasting pan on a stove top burner. Add 4 cups water and simmer, stirring to loosen up brown bits on bottom of pan then add to stock pot.  Add the bay leaves, parsley and thyme.  Cover and simmer over very low heat for 5-6 hours.

Line a large strainer with a double layer of cheese cloth and place over a large bowl or container.  Remove stock pot from heat and pour liquid through the strainer allowing the bones and vegetables to fall into the strainer.  Allow stock to cool then place in refrigerator until any fat has risen to the top and hardened. Remove the hardened fat and discard.  Ladle stock into individual containers, if desired.  Can be frozen.