I would have thought they're OK (under supervision) for a toy breed, my Rotties try to swallow them almost whole, so they don't get them anymore. Just keep an eye on them and when the remainder gets small enough for them to consider swallowing it whole - take it away.
My friend's Cavaliers always have them with no trouble. I don't give mine anything that they take a long time to chew and eat, because I end up with one dog sitting on the the whole lot and the others looking miserable!
I give my lot pigs ear strips as a treat when they go to bed,they lie down and just chew them slowly as if savouring every bite! They have never tried swallowing them whole as they are all in their own beds so no threat of it being pinched by anyone.
We have a Boston and a Boxer the Pigs Ears from the Pet Shop were too small for her as she tried to swallow them whole then we used to get Sows Ears from a stand at Ardingly and they were huge she has since been diagnosed with inflamatory bowel disease so now no more of these for her as the fat in them upsets her and the Boston has fat free Venison Ears from Burns,she is never left unattened with one and has this when the Boxer is out with OH.Debby