Liz Buchanan BVSc MRCVS
Hello! I'm sure that there have, in history, been occasions where animals have eaten bones with nice rounded edges and have had them settle nicely in the stomch where they havent caused any issues for prolonged lengths of time, or where spiky ends have been protected with food for a while. However, there have been many cases where sharp bony edges have perforated intestine or stomach and led to peritonitis, which is life-threatening. While you dont mention the size of the bones, young jack russels arent very big and they have narrow, bendy guts. This is a decision that we reccommend your vet at least has a say in.