this is basic bones and raw food principle

55% muscle meat
15% organ meat including tripe
15% bone
15% vegetables including other products

or

50% fleshbone
20% muscle meat
15% organ meat including tripe
15% vegetables including other products


so 15 to 20 %, i think adding more bone wont harm nor does have any benefit to your dog. 40 % bone wouldnt harm your dog, but it means less % of meat/organs,ect
it doesnt matter if you feed that once or twice a week, but if someone feeds 40% bone consistently i consider that one shit menu