What a cutie!
I've had 5 ratties from PE, and only one was friendly to start with.
A lot of patience, and a little peanut butter on the finger drew all of mine out of their cages to eventually become some of the most loving rats I know.
It's hard, but be patient and they should come around.
Here's a pic of my most recent rescue from there, a blue named muffin.

keep an eye on your kids, it's possible that they have "the sneeze" as most of the PE rats do and part of their misbehavior is being sick. If you do have to take them in to a vet, I recommend Creekside. They've treated my girls wonderfully.
Good luck!
Anna
