If you get rats or mice visit this forum
Rat & Mouse Club of America
Especially visit their
forum. The site is a great resource to learn how to properly care for your mouse/rat. (you need to become a forum member before the forums are viewable.)
My wife and I found this site a little too late.
We had to mice, one caught rat influenza and died rather slowly. It was hard to watch and we learned many things from the experience
#1. Do not feed a mouse any kind of packaged rodent food (or any rodent pets for that matter)
The food tends to be infested from time to time with rat influenza and can get your pet terminally sick.
Mainly feed them fresh veggies and dry goods that you eat yourself.