It's better to er on the safe side and wean earlier for this reason. I wean as soon as I see the runt of the litter eating solids and drinking from the water bottle.

Getting prego too young can stunt growth of rodents or result in complications at birth. Both mother and the litter can die of these complications. The size of the rat can make a big differernce in future health and litter size so better to wait for them to grow up a little.

Plus unintentional incest is never good. I say 'unintentional' because some people do line breed their rodents with no ill effects.


Hope that helps,
Cheers!