Eating your own children

im just going to give my opinion and say its wrong to eat your children, yeah they might be a pain sometimes but thats what you have to deal with when your a parent

A 20 long with three adults and one or two litters of baby rats may be just way too overcrowded and causing this female to turn on her litter and destroy them. Personally I remove all females as soon as they are pear shaped from the big breeding tub and pop them in individual 10 gallon tanks (I generally have 5 or 6 tanks running with females/litters of various ages). I've not had a female do anything more than culling one or two runts from the litter at or very shortly after birth.

Try removing this female to a seperate 10 gallon, give her lots of bedding and some strips from an old telephone book and leave her be with lots of food and water. See if the privacy and lack of stress affect her mothering skills. If she continues to turn on her litter, then feed her off and I personally would not keep any of her offspring as future breeders as breeding/mothering skills seem to be somewhat genetic in rats. I had one female suddenly go rogue and start killing off her almost pup aged babies. She also became crazy mean with Mike and I and was biting nearly to the bone if we approached her even to feed/water her enclosure (she'd always been nippy but she became dangerous to work with). In that case we did put her down and fed off all her offspring as we were never sure what caused her to suddenly turn so vicious.

She may well be reacting to the small space or being dominated by the other female rat (females can just as territorial and dominating to each other than males are, sometimes far worse actually).

So do you think the 20 long is too small for the adults only, or adults plus babies?

Probably just a bit too small for three adults and one or two litters really. Rats are busy creatures and do need a fair bit of space in my opinion, especially the bigger adults. Some of my adults are quite huge rats (huge bodied not fat).

Rats do tend to get obese and unhealthy, tempermental and territorial when overcrowded in a tank that's a bit too small for their current numbers. I know lots of folks leave their breeding females in communal setups but personally I've just never had that much success with it so I pull mine to 10 gallon tanks until they wean the litter. Especially with a female though that's turned on litters like this, I'd certainly give her one more shot in a private maternity tank with little stress. See how she goes, she eats them again, I'd cull her. She may be fine though alone with her litter. You won't know till you try and see what happens.