True Patriot
Sanity is subjective
Some chicks are greedy and will pack their crops full, others are happy just topping off periodically. Withholding food from a young chick can lead to other problems. They really should be able to eat as much as they want when they want. If you can, follow casportpony's advice and have a vet do a fecal check. Other than that it sounds like a pretty normal chick.