I'm right there with ya, Jo! I've never bred rats, but the mice are frustrating me to no end.

I do have mine in dark enclosures with a mesh opening on top. Right now I have 3 different tubs with 3 different arrangements of mice in them, as an experiment to see if I can get *any* breeding done. Out of 5 recent litters, I have 2 tubs with one baby each left alive, and one tub with 2 babies in it. GAH!!!!!

I do have water bottles on the tubs, only once did I have a mouse try to chew around the hole. We put packing tape around the hole, and no one has bothered it since then.