What should I do

Normally when one rat from mine was going to give birth I put her in a ten gallon tank until I fed of the babies or they got weaned. But that's when I had 6 rats now my cousin gave me his 3 slot rack so I decided to put them in there. The top row I put 1.4 ratio two of them gave birth for their first time today and are doing a good job I left and when I came back a female rat who I fed off her babies like a week ago took like 6 from the two. Is it alright for her to do this and how long after they lose their babies do they lose their milk.

If she didn't take all the babies from the others, all is well, just monitor her her to make sure the babies are well nourished.

This happened to me recently as well. Problem I had were the mothers playing tug of war with the babies. Ended up with some babies with nasty wounds. Works okay if you've got moms that have given birth close too each other. They'll work together and nurse the whole litter. In my experience, not so well with a mom that has her older litter fed off. Keep an eye on the younguns.

Well I decided not to risk it and put the two females together in a 15 gallon long. And I put all the babies together. They were literally giving birth at the same time. Now they separated the babies and found their own corners. When I look at them they seem awkward like what are we sopose to do couse this is their first time. They have some babies under them some to the side and behind them. I only worry if there not kept warm that they will die.

I foster babies all the time. Most of the time, a momma rat will care for babies, no matter whose they are. If I have a cage that has a couple of huge litters, I'll take some out and give them to a cage that has less babies in it...