It looks a little thin, but not emaciated. Most hatchlings I've had grew more than that, but every one is different and all my balls are started on appropriately sized rats. There is no reason to ever feed mice. Now that its moved onto rats, there should be a major difference in growth. At its size it will have no problem eating much larger than a pink. Fuzzies or so would be better. 1-1 1/2 times as big around as the fattest part of its body.