We give raw marrow bones to Thor frequently, but with some restrictions:
* only full-sized. A lot of butchers cut them into smaller pieces for easier consumption but if thor gets a smaller one he'll try to swallow the whole bone. We buy giant uncut bones (~10-12 inches in length) from a local butcher for cheap. We store them in the freezer and give them to Thor frozen. He'll lick and lick and lick at the marrow as it thaws and not try to eat the bone itself. With the smaller cuts he'll go for the whole thing and it will make him puke for days. Luckily no obstructions because we figured it out pretty quickly.
* always supervised. Once he gets through most of the marrow and gets bored he might start trying to tear apart the bone. Usually he'll go try to bury it somewhere in the cattle pasture. We'll try to catch him before that happens otherwise he'll dig up a sunbleached and brittle bone later on, and those are no good.
* cut back on his next meal. Marrow is rich and calorie dense. We cut back his next meal to correspond to the amount of marrow he ate. This is a really fuzzy measurement - a lot of times he gets a marrow bone after a long day of hiking so we won't cut his meals back as much then.
* EXTRA POOPS. On days where he has a marrow bone he almost alway has an extra poop before bed. If we don't let him out for the extra poop it will end up happening on our bedroom floor in the middle of the night. This is like clockwork - I'll go as far as setting a reminder in my phone whenever I give him a marrow bone to let him out an extra time before bed.