mother rat

Question
I am mortified to even have to ask you this but I made a horrible mistake which turned into an even bigger mistake that led to the death of all but one baby rat. However, it happened and now I would like to know how to proceed. I agreed to foster some babies from a friend. I thought I was pretty good at sexing but it turned out that I missed one girl and put her in with the boys. A few days ago I noticed a lot of squealing and that 2 of the boys were humping another. I have had these guys for about a month and they are not much more than 10 or 12 weeks old. Well, the one they were humping turned out to be a girl. I quickly got her out of the cage and thought all was well. Not so. Not only did I miss the sex of this girl but I completely missed that she had given birth!! I know I'm busy but my goodness, this is truly a humbling wake up call that I am not as attentive as I need to be! I even handle these rats and still I didn't notice! Anyway, the boys made quick work of the babies being with the mom and started to eat them. I heard that familiar baby squeal and ran over the cage to discover a whole nest hidden under a house. I panicked and grabbed all the babies and put them in with the mother. She must have felt terribly threatened by all of this because in the morning all but one of the babies was gone. She had eaten them. I realize I probably should have figured out how to build a barrier in the cage to keep her and her babies separated from the boys to keep all of this from happening but I didn't think in the moment very well. Now I am afraid to go near her because I'm afraid she'll eat this last one. However, she needs to eat. It's been 2 days and I did put a scrambled egg in there with her today since she was low on the food I put in there when the babies were alive. She ate some and went right back to the baby who is still alive. I feel just terrible and completely stupid. I'm not new to rats and I've been around babies and birthing and I know the "rules" and still I let this all happen. I'm sure she's pregnant again since the boys were most definitely mating with her after this litter was born. Any advice on how to proceed? I am fairly certain that she was taking good care of them for the day or two that they were around before I moved the whole lot and caused this disaster. Do I need to worry about this next possible litter having the same fate? And if so, is there any way to provide for them without her?

Thanks.

Answer
there is a chance the stress caused her to stop lactating.  Mothers dont eat their babies for no reason.  They do it for a reason, which is usually when they cant feed them.  Check this last pup for milk band, see if she is nursing it.  Nature can be cruel, dont blame yourself.

If she did stop lactating, she may have a problem next time, but its not a sure thing. I would try to locate someone that breeds rats, try to find a surrogate and put her on stand by. Do you know of any breeders in your area, perhaps try a pet store?