I’ve got a very small rat breeding project I’ve recently started up. I’ve had 1.2 rats (now 10 weeks old) in a tub for a month now and so far no babies. I’m not sure if either of the females are pregnant or not, I don’t know what to look for.
Are there any signs or ways to know if one of them is expecting or should I just keep waiting?

Backround: Rats have an unlimited supply of water and Harlan 18% protein lab block overhead and are kept at a consistent 75-77 degrees