I had this problem with my beardie when he lost his sense of smell (and the poor guy was on prednisone, too). What I did was warm up his food just a little - that made the smell stronger and he'd eat. Maybe if you serve his chicken and rice warm(or whatever you want to add), then stir it into his dog food, he'll like it better.
[image]http://www.imagestation.com/picture/sraid225/p5e50477ef63ae4cdeb62570d23601ebe/e89ec0aa.jpg[/image]