Corns at 5 months of age should be on small mice. If given proper husbandry (i.e. temps, humidity, etc) cornsnakes CRUSH mice!! I feed hatchlings two to three prey items every 3-5 days. The key is proper husbandry allowing their natural metabolism to function. In nature hatchlings try to find enough prey to gain size as to not become a prey item themselves and to recruit offspring as soon as possible.

Cheers,
Ken