Get large ones and take it away when it is small, trade off with a treat if you have to. When small-bite size-put them in the microwave for a minute or so. They puff up and are safe so no choking hazard then, crumbly. Just don't over cook, they are done when they stop "growing" I feed raw also and they get these on occasion no problem. I'm a worry wart too :-)
Sometimes i break them on purpose and microwave them, they smell wonderful that way and i think my dogs prefer them.