In that picture he does not look thin. Would need an above shot to be definitive. He looks like he can take larger food than mouse hoppers. Mouse hoppers are usually fed to hatchlings. Some of mine are too big for hoppers out of the egg.
As too dropping his food...
Some of these guys like to play with their food before eating it. It is not unusual. I have a couple that will sniff prey for a half hour before actually eating it. With these animals, I can accelerate the process by totally covering the cage until it has swallowed.