What kibble are you feeding him? If it's a good kibble, he should probably want to at least try it. Try adding a little water to the kibble to bring out the aroma and soften it a little. Eventually, lessen the amount of chicken and rice and increase the amount of kibble. You may need to employ a little tough love. A healthy dog won't starve himself for long. The longest one of mine has held out is three days. If you're going to keep him, a vet visit is in order, as mentioned above.