My male Rats are 6 months with no balls! Are they boys?

[Angie]

The testicles start to drop when they are around 2.5 weeks old but you are able to see them when the male rat is as young as 3 weeks old. No, they are not sexually mature at this time, not until they are 5-6 weeks old.

You need to observe your new baby as it relaxes in it's cage. As soon as the boy relaxes the testicles will drop. If the testicles don't drop then you have a female.

You can also look along the outer edge of the belly and chest for nipples. If you find them you have a female as male rats don't have nipples. Hope this helped!