My new pup can't eat raw chicken bones?

She is a 9wk old Italian greyhound.. I fed my sheltie raw from 8 weeks and he crunched bones like a maniac from day one. The IG will sit there for half an hour chewing on the bone.. and nothing happens. I've been cutting them up into bite sized pieces but I don't want to do this forever. She has tried chicken, cornish game hen, fish.. nothing. Any tips? She has TINY puppy teeth and her mouth is mostly gums.. should this get better as she teethes? At what age does a normal dog teethe?