Corns are typically fiesty, fast and nippy as babies and slowly begin to chill (less nippy, less fiesty, not as wiggly and fast during handling sessions).

My corn, who will be 2 years old in late summer, is really just over the past 2 months or so started to calm down and be handleable, although he hasn't been nippy since a few months after I got him.

Go slow and do regular but not too long handling sessions and hopefully your corns will learn that 1) cage opening isn't always food and 2) you're not going to hurt them so they don't need to be defensive. =)