We 'hang' meat like hams for ages, this is probably his way of maturing the bones! They probably taste better after a couple of weeks buried.
I used to have a Belgian Shepherd who loved meat etc. when it had 'matured', we used to joke that she saw the maggots as a bit of extra protein (they eat them in the jungle don't they?). Used to have to watch her like a hawk on walks in case she spotted a rotting carcase, once in her mouth you had zero chance of getting anything back. She died of old age, so it never harmed her!