This would also be my recommendation also. I had a sav. years ago that all of the sudden went off feed. I took him to the vet and everything checked out fine, a few days later and still no eating.Took him to a different vet and as he was doing a mouth swab we found a tiny piece of substrate lodged in the rear corner of his mouth that was causing irritation you really had to look hard to see it, we removed it and as soon as I got back home he was eating perfectly normal.