Hm..Hmmmm...I feel much better now. Thanks for the advice.

I'm very much convinced that rodents in the feeder bin would not be good breeders, unfortunately pet shops here don't have pet rats nor mice. So I can only try the numbers game. Hopefully in time I can get enough good offspring from them.

I think the few colored mice from that one shop would be the best bet for my future mice.

I guess I'll have to order the new 20 rats to start all over, hopefully in a couple years when I need those big rats as feeders they will be breeding OK!!