Well I went to check on my other girls, and one of the females that didn't look so heavily pregnant, is having babies too! Woo today is a great day to have kids for my rats lol.
My husband thought it was odd that one of the igloos was stuffed with tissues in the doorway, so he was pulling out some of the tissues to look inside and see who was hiding, and Beth bit him! So I said "maybe she is having her babies..." But I didn't think she was... I was just making an excuse for her biting him so he didn't start hating her lol. And I lifted up the igloo and sure enough, she has one baby in there!
She's in a large 6ft x 5ft x 2ft cage with 4 other rats, and none of them are bothering her at all, so I think I'm just going to leave her for now.