Omg, ok... Trying not to laugh but that is a great pic. You either smelled REALLY nummy or your little guy needs a snack. I commend your camera skills if you were able to hold it and get that pic.

ok, serious time... Do you have a scale and have weighed him? Your 3 year old looks about the same size as my 1 year old. If she was feeding him small mice, I hope it was about 3 at a time. He's easily big enough for a small rat. This is where it will get fun....you probably need to leave him completely alone for a few days to let him settle and then try to feed him. A switch to rats might be tough if he's used to the mice. If you do the mice, good lord... 3? Getting him eating might be fun given stress etc but judging by the pic? He's got an appetite.