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[reptilemart]

I used to keep 3 tubs of 1M 4F, and I never had the problem.
They were kept on the garage floor too, so in terms of being disturbed, they would be disturbed all day. I used to check on them every night. If one of the mums looks like she is going to drop, I would temporarily empty out her tank mates and spread them into the other tubs. As soon as she drops I just put a small plastic tub in the larger one and she would nest and guard them. Once she has the nest setup, I would return the tank mates.. I usually only wanted pinks or fuzzies, so they were never left that long. Towards the end of my rat breeding adventures I did require adults and would basically put the weaners in their own small tub until they hit small adult size, then reintroduce them to the others, etc..