I have two girls that are about 6 months old. I've had rats before. The rats I had before were from a good local pet store, they were properly handled and not skittish. That pet store closed down, and I got these rats from petsmart, which was the dumbest decision I've ever made. They hadn't been handled much and certainly not very well. The worker even picked them up by their tails! It was hard getting them to adjust to me and they are a bit less skittish now, but they still are not like my other rats have been. They chewed through their old cage, escaped and chewed up our carpet. We got a new cage with a metal bottom they are happier in and can't chew through but they still like to try and escape at any chance they get. They aren't fond of being held, they won't bite me anymore but they do occasionally nip at my fiance. I've never had rats so troublesome before. I try to handle them as much as I can but them constantly trying to escape that makes things difficult. I love them to pieces but I just don't know what to do to make them more comfortable being handled and more calm.