Problems with rat colony

[jwsporty]

Here's the back ground

I am taking care of a group of 1.3 hooded rats for a friend that got them with a snake purchase. They are all adults and should be capable of producing. Problem is since I have had them in the system(which has been about 2 months now, only one female has given a litter and it was small (6). Problem is we do not know just how old this group is. So should I simply say screw it and take them all down and start all over? Should I take out one of the females and introduce her into a new colony? Should I take down the male and replace him and leave the females? The other colonies are doing fine and producing pretty much on schedule.. Incidently the care and cage setups are similiar to my groups so I know that is not an issue.

For those long term rat breeders how often are you switching out cagemates or starting fresh?

Any help?


Thanks

Jim