Rats are prey animals, they are in a new area, that bin has a great deal of height and I don't see any hides for them is why she is staying close to him. Rats are also very, very social animals. The male is not going to be very happy being on his own from birth to weaning. Would you be able to at least give him some environmental enrichment to help him out a little bit? Maybe a hide or something to chew on?

I know you didn't ask for my opinion, but I'm going to give it anyway
You might want to consider holding back 1-2 male rats from the litter to keep him company during his separation. That will of course require a larger bin to accomodate them. There are individuals in the herp community who will cram as many rodents as they can into small bins and yes the animals will live and reproduce, but since they are giving their lives to feed our snakes, we should be giving them more than the bare minimum needed for survival.

Good luck with the upcoming litter.