That's very interesting thanks.
I don't feed fresh food to my chinchillas, just to clarify, but they share the dry forage my rabbits have such as plantain.
I had no idea chinchillas had a cecum and produced cecotropes. Going to have to do some more research now. I have an ill rabbit who can't eat hay and produces a lot of excess cecals so I'm used to seeing those.
It seems their digestive systems are very similar, so if the reason rabbits aren't rodents is due to that then it makes no sense if chinnies are. The teeth are also interesting. I know chinchillas teeth are very different anyway. They have a coating of iron which gives them the orange colour. Rabbit have peg teeth which grow behind the incisors. I don't know what purpose they have other than to annoy me. My ill rabbit had his front teeth removed and one peg tooth continues to grow. If it's the teeth that cause the difference in classification then that makes more sense.
All very interesting.