Could they be pregnant?

I have 2 female rats, they both had litters and when I was pulling the weanlings, both females looked big, almost like they were pregnant.

So my question is, do they retain sperm? and could they be pregnant?

They can.

Also watch out for worms or mega colon.

Ok, I will put them back in maternity ward then to keep them isolated, Thanks :)

I notice some of my females swell a little right around weaning their previous litters. I've never really looked into why, I'm assuming it's because of extra calorie intake.

I've never had a female retain sperm so close to having a first litter. Actually, I've never had a female retain sperm at all, that I was aware of.

I wouldn't have a problem putting them back into the main tank, but it's a pimp pad, so I'll let them hang in maternity for a week or 2, to be on the safe side