Advice on pregnant rats

hello, everyone!

today i brought in a female rat, as my friend had a friend (the previous rat owner) who decided he didn't want to own a rat anymore, and was going to release her into the downtown city. my friend instead said she'd message me, as i own rats, to see if i'd take her in and of course i said yes!

i own 2 rats of my own, but since both are males, and i don't have around $280 to drop to get this gal spayed, i plan on rehoming her to someone who already has female rats she can be cage mates with. however, before my friend left, she told me that the previous rat owner had allowed his rat to have a playdate with a male rat.

unsupervised, no less.

that was about a week ago, so now i'm going to hang onto this gal to see if her belly grows larger. she had a really bad diet from what i understand, so i'm unable to rule out if she might be putting on baby pudge or gained weight from a diet of "cheese burgers and croutons" (i know, i have a lot of questions too)

i've been talking to my rat breeder to get some general advice on what to do IF this girl does turn out to be pregnant, as i know of no rescues or shelters in my area that take in rats, and trying to rehome a rat without knowing if she's expecting isn't a stress i'd want to put on anyone else! i've never had young rats before though, the youngest i've owned are my two boys who i got when they were a month old, so any advice i could get would be very helpful, just to prepare for the worst-case scenario.

this gal came in a cage that has dimensions of 24x14x15, which from the several calculators tell me CAN house 1 rat. i plan on fleecing the bottom and also hanging a hammock or two in there if i can squeeze them in, and probably give her a cardboard box with some fleece scraps or toilet paper, or just anything that she can nest around with. the cage has a pretty deep pan on it actually, and my breeder doesn't think any baby rats would be able to get to the bars and / or hurt themselves on them. (i can attach pics later if people want to see it! currently washing some fleece so i can clean and remove the unidentifiable wood shavings)

i've never had any interest in breeding rats, but if mystery babies fall into my lap i'm going to do my very best to make sure they survive, grow, and get good homes of their own!

update: attaching a photo of the cage!
when i measured it, it comes out to 24½ x 14 x 15. i just finished scrubbing everything down and making a super quick fleece liner (i have to sew everything by hand, yikes) and trying to find some stuff i could chuck in there to give her something to do. it's by no means perfect, but i still feel good. this is progress.

Nice job
glad she is safe with you.
Do you have a digital scale that weights accurately to 1 gram (easiest if it has a tare function)? If not please get one as they are important to have.
Weight her each day at the same time and record her weight so that you can see if there is a pattern. Most weight gain occurs in the last week of pregnancy.
If she gains weight, post pictures of her showing her belly from the front and side and we can let you know if she looks pregnant

Gestation is 21.5 to 22 days and average litter size is 12 to 14 babies, although litters can range from 2 to 26 babies.
Once the babies are 2 to 3 weeks old that cage will be much too small as babies need space to be active, explore etc
Feed her a healthy diet, when she is close to giving birth you will need to make sure there is nothing in the cage that contains threads as they can tighten around little limbs or necks, and no hammocks or levels as babies could fall. Fleece is ok and you will want to provide strips of paper towel for nest building.

Mamas will gradually wean their babies, and after their eyes open babies will start trying the food their mama eats as they learn from her. baby boys are separated from mom and sisters at 5 weeks, baby girls stay with mom until at least 6 weeks of age and never need to be separated. Note: babies need to be at least 8 weeks old (10 weeks is safer) before being gradually introduced to unfamiliar rats over 12 weeks old - and young babies do not smell like rats so older rats may mistake them for prey and kill them.

Make sure you have access to a good vet with the knowledge and experience to treat rats and do surgery on rats …. in case she has problems during or after birth

Please see our Reference Thread for information on pregnancy, birth, babies etc https://www.ratshackforum.com/threads/reference-thread-read-only.35894/

Sounds like that poor girl is having a rough life, thank goodness you got her. That cage makes a good maternity cage, definitely not a good long term cage. Rats make really good moms so I wouldn't worry too much.