Now, I understand this forum is for pet rats, but I do breed rats for feeders. I had a litter of babies less than a month old, and one of the babies was pregnant. This wasn't any sort of tumor, the lumps were on both sides of her belly and I've seen many pregnant rats, this was definitely one. She was at least 2 weeks pregnant, so I'm wondering how this even could've happened? She would've been less than 2 weeks old? Unless it's very rare that some rats can be born pregnant? I'd love to know what happened so I can try to help avoid it in the future. It was very sad and I had to put her down.