Allison I buy the bones from the butcher section of the market. Sometimes I call ahead to be sure that he has the long bones and in the quantity that I want. If there is too much marrow, ie if they are very stout bones, I scoop out some of the marrow. I suspect that some dogs will have a stomach reaction to the rich marrow. I also fill them with kibble and peanut butter for a "treat".
Esta Dalsass NJ