Here in Canada we call them soup bones, just take a bit of the marrow out as too much can give them runny poop. But otherwise they are really good for them.
My hubby actually went earlier in the day and he gave him bones big enough for a Great Dame. Anyway I went back later and they will cut them to the size you want.
Just tell them you want small bones about 3 to 4 inches, our grocery store has a butcher counter attached to it so I usually ask them and they will cut them for you.
They also had some turkey necks, which usually I would never buy but they looked more like the chicken necks I buy so I got a few of those too.
These boys are gonna have a field day this wkd.
Let us know how you make out Monica, don't you feed NV I think some pre-frozen raw foods also sell marrow bones.
But you are better to get them fresh if you can.