Bones are cut into 3 or 4" pieces and are from the neck
Beef soup bones are the key to a hearty and rich soup. You also can use them in a stew base or stock for extra flavor and health benefits, such as added collagen from the bone marrow. It gives the soup a tremendous taste and allows for the use of more of the cow in the cooking process, a must for amateur and professional chefs alike.
Soup bones, also known as stock bones, are leftover pieces from the butchering process. Home cooks often don't use them or throw them out, which ends up being a waste. These parts often have small pieces of meat left on them, which won't make for a full meal but which are flavorful and add depth and complexity to soups or stews. The bones can go in with onions, carrots, and celery in a crockpot or stockpot to create a delicious bone broth.
Soup bones carry flavor from the leftover meat pieces and the bone marrow, adding rich flavor to the stew or stock. Bone marrow contains collagen and other products that have health benefits, so when soup bones go into creating a stock, the bone marrow infuses into the stew and gives you those benefits along with the lovely flavor.