Just a quick note. Shortly after I replied to this message I had a first time mother rat have a difficult birth that resulted in 3 stillborn and 8 babies that she ignored. There was another female in the bin with her that was close to giving birth.
I moved the neglected newborns to two other female rats that recently gave birth and they accepted them just fine. I just checked on the the one that had problems and her roommate recently gave birth. The mother rat that had problems took several of the babies and was successfully feeding them in her nest.
It does take a while to raise up a healthy female to breeding size and I prefer to give them a chance if I can. I agree that chewers, aggressive rats, and problem breeders should be culled, but I think mother rats that may have had a bad litter shouldn't be put in that category.
In the end, you should do what works for you.![]()