I would probably say pups, but one persons rat pup can be another's weaned.

The best thing to do is just go by weight. The Rodent Pro site lists the weight range for each size that they sell so all you need to do is weigh your BP.

Bp's should eat rodents that weigh 10-15% of their body weight.

*example*

so a 100 gram BP should eat a 15 gram rodent (100 x 0.15 = 15)