Kay, it's pretty common for dogs to throw up a little bit of small bone fragements when first switching over. Mine have all done it, Kaige was worse than the others, and many others that I know of have done it too. Their bodies are adjusting to "different" things to digest, raw digests differently than kibble.

Do you find it happening more often in the morning (if you feed raw at night)? And do you find a little bile with it as well, or actually its a yellowish foam? If so it is probably because they have an empty stomach.

Either way it should go away within a few weeks once on raw, once her body becomes used to it.

You can try adding some yogurt with active cultures or some digestive enzymes for the first 1-3 weeks to help his digestive system handle this new switch.