At what age can you give a dog marrow bone ? My bc is 9 mths old - is this too young to give her a bone ?

Certainly not too young, my 3 week old puppies were trying to eat bones :) Try her first on a knuckle bone though as I've found the leg bones sometimes have too much marrow and can give them the runs.

edited to add... if you click on my name and look at my photobucket site I've just uploaded a pic of my 7 week old pups sharing a bone, although it is a horrible one that Mum had buried in the garden several weeks before

I dont think there is a minimum age,i dont breed so have only had dogs from around 8 weeks old and i've started them all on bones straight away.FYI they are great for when pups are teething,although you're probably way past that stage now :)

I give my puppies meaty knuckle bones from about 3 weeks.

We got Sirius his first marrow bone from the butchers today and we have hardly seen him he has been out in the garden with it for most of the day....:D

Go and check him,you will be surprised how many holes these cheeky pupsters can dig to bury a single bone,I think Travis is trying to booby trap my garden with holes he has dug

when ever I give my dog a bone, she only eats the marrow, she has never eaten the actual bone. maybe had some tiny bits of it but nothing major. Is this as issue? (she is fed nature diet)

Marrow bones are considered "recreational" bones, they are not designed to be consumed (necessarily).  The marrow is very nutritious (if a little laxative in quantity) but many dogs find the bones themselves a little too challenging others, like mine, think nothing of devouring one.  As they come from bigger, older animals, the risk is that dogs break their teeth on them.

I generally try and remove mine once all the cartilage, marrow etc has been removed, however sometimes I forget.........

No its not too young. My youngest pup has been having them from 8 weeks. Just watch they dont have too much marrow initially as it can give them the runs.