Yeah, sometimes they just pack the mice in without weighing them to save time and money. I have to feed my babies tonight so I put 5 pinkies in the container to thaw, and as I go to each viv I can tell by their size which pinky would be best for them. There is no correct science in picking mice unless you have a lot of time and can separate by weight. This is where the "eyeballing" the size comes in handy. I have babies from 10g to 25g so I pick out the smallest for the smallest... you get the idea!