How old is the pup?
When our Spaniels were pups they would get the occasional knuckle bone, but it would always be roasted as it is easier on their teeth and gums due to being a bit softer.
As they are now older, they get the hooves and lower legs of the fallow and roe we shoot, and it doesn't cause them any problems, apart from making them a bit bunged up inside.
We have always stayed away from the ribs and similar as they can splinter quite easily, and have always been led to believe that lower legs etc. are better in terms of bone construction and are at less risk of fracturing into shards.
ATB with the new pup,
Sandy