These bones are NOT the meaty/fully consumable bones you need to use to balance the diet. They do not provide adequate calcium in the diet because they are not meant to be fully consumed. They are entirely optional and many choose to avoid them entirely.

Recreational bones are are dense bones that are: stripped of meat, mechanically cut, weight bearing bones from large herbivores. They are the highest risk bones to feed. Bones in this category are at high risk for breaking teeth, they can get caught/wedged inside the mouth, jaw or throat, and they can break into sharp shards that may cause damage to the mouth or GI tract. 

However, they make excellent broth, and roasted marrow, served scooped out from inside the bone, is delicious and nutritious!

These bones are really only suitable for individuals that do not bite down hard; those animals that simply lick and savor the bones as a treat, and not attempt to eat as a meal.