Ok, here's what I've got.
I have had 1.3 breeder rats in a 20g long aquarium for about a month and a half. One of my females had a litter of 9 at the end of September, and they were raised and fed off successfully. Two weeks ago, another female had a litter of 13, and ate one, leaving 12. This last week, another female had a litter of 15, and today there are only 9!
I have three females who are sharing nursing and ratsitting duties between 27 babies. Would they have eaten 6 of this week's pinkies because of overpopulation in the tank? All the pinks looked healthy at birth, and were ok for the first couple days. Today they are just gone.
I guess it makes sense if they are practicing preemptive population control, I just wish I had thought of it sooner.
Oh, and I did move one female and the 9 fuzzies out to a different tank today.
Opinions?