can rats breed through the bars?

Question
Ok, so I keep my girls and boys in separate cages, but i take turns letting them run around. Now when the girls are running around they can climb on and around the boys cage, and vice versa. For a week or so now i've noticed one of my girls is a little fatter and is building very large nests. She's acting just like a pregnant rat. Is it possible for rats to breed through the bars? Cuz i can't think of any other reason why she would be acting like that. I'm worried cuz i'm already struggling taking care of the rats i have. I don't think i can handle another litter. I'm also worried because if she IS pregnant, her own son would have gotten her pregnant.

Answer
Yes, it is possible to get her pregnant, Slim but it is not unheard of.
I would recommend a vet visit to be sure. If she is dont stress about the litter, once they are old enough you can use Petfinder.com and people take them pretty fast. Her breeding with her son on the other hand is very bad, but it was not intentional. If you get defects,such as missing limbs, Or strange illnesses, thats why.

I hope I could help!

Emily Harris