Big litters

Three litter is usually the maximum suggested. Did you give her recovery time before she got pregnant again? How old is she, approximately?

I'm not sure how old she is, I've had her only eight months or so and got her at a pet store. She seemed and acted young (under 6 months). I rested her about a month in between and I'm thinking I ought to retire her now? She's had a total of at least 45 babies. I would not have believed they were all hers had she not been alone.
I feed a store bought mouse food supplemented with oats, wild bird seed (niger primarily), and a small amount of good quality dog kibble.
Thanks again for looking

Yes, I would retire her.