Thanks for the responses! Perhaps I'll keep a larger group together to ensure that they are breeding ok. I'm happy to hear the smell issue is better. The worst part of keeping mice is the stink! Just a couple mice smell so much more than twice as many rats, its crazy.

Perhaps I'll keep an eye out for some 10g tanks on craigslist and freecycle. It sounds very appealing that I can let them grow out with their parents. I'm sure after I get some experience I'll figure something out that works for me.

I've noticed one of them has really crusty swollen eyes. It seems this is a fairly common thing with these guys. Is there anything I can do? I tried using warm water on a cotton ball to wipe his eyes, but he didn't tolerate that very well. Should I separate him? I don't think I can feed him off, hes smaller than a golf ball and it seems silly to feed that tiny little guy to a 1300g ball.