Nursing baby rats

Question
My rat Darcel got out of her cage while i was cleaning it, And i didn't catch her til recently, she was out for over a month. She was in her cage for 3 days before, one morning i woke up and found a tiny baby rat on the floor, he had fur, but did not have his eyes open. He was cold and starving. So i wrapped him in a baby blanket and tore my room apart looking for where he came from. i found a litter of 7 under my heater. And soi grabbed darcel and put her with them, because she was the only possible mother.Even though i'm not sure how she got pregnant in the first place. She tried but could not nurse them, she lifted up for them to nurse,then would shake really bad. Then run away from them and hide. i'm not sure if she dried up. But i had to nurse them myself. i started for the first night,every hour. and fed them soy baby formula as much as they wanted. Then after 2 days they were stronger and doing great,so i went to every 3 hours. now one of the babies has gotten thin,and his stomache looks caved in, i've been feeding him every hour. he is weak. and i figured i should go back to every hour for all of them. its hard for me getting up all hours of the night and early morning, i'm 5 months pregnant and still fighting being sick all the time. so i feel like i'm doing something wrong with sometimes sleeping through my alarm in the middle of the night to feed them. How often should i feed them,and how much. What more can i do to ensure their health and safety? i've been hand raising them for 6 days today the 19th. i'm happy they have made it this far. But it looks like things are getting worse, there is only 2 that look at a healthy weight etc. all the others who aren't up to parr i give extra attention and feedings,to try and get them healthy but nothing seems to be working. also they are very dehydrated. i slightly pinch their skin and it doesnt go down at all. i have to put it back down. how can i get them hydrated ???
Thanks so much in advance.  

Answer
Eek!

First of all, don't blame yourself if you lose any of them - raising orphaned babies (essentially they are) is VERY difficult! I have only had success a handful of times, my failures were far more frequent.

I would switch them onto Kitten Milk Replacement ("KMR") which you can find at any pet store. Feed them as often as they'll eat, which right now should be every 1 to 3 hours. If their eyes are open, you can start feeding them soft, semi-chunky foods (like jarred baby food) off of a plate, and that will help gain weight. Unfortunately, if they went 3 days without any source of nutrition, they may already be too malnutritioned to save. Good luck though, and I wish you the best. And by the way, congratulations on the baby!