Thank you for your response.
I did in fact change his pellets recently from Kaytee Timothy pellets to Oxbow Alfalfa-based Deluxe Chinchilla feed. I give alfalfa hay and timothy hay with herbs, as well as some fresh Meadow grass (all Oxbow). I was giving him wheat germ mixed with raw oatmeal (tiny bowl, just a pinch 3 x p week) and some papaya and pineapple (dried bits without sulfite). I will have to cut down to simply the pellets and the hay.
I just hope he can come out of his current state. I cannot keep going back and forth to the vet, and leaving him overnight, only to be told he is basically fine - but the continued noneating and tiny, hard droppings.
I intend to take him back to the vet and ask for the intestinal parasite check, and perhaps an Xray and I cannot think what else.
He has only wooden chews and a wooden hut and a lava ledge - there is no cloth and no plastic that he has access to. He also has a very large wheel to exercise on and a crock full of fresh water plus a water bottle and all is kept clean and fresh.