Hehehe yeah the mice have the 1/4" hardware cloth and the rats have 1/2" hardware cloth. The drop-down hoppers are removable and allow even the smallest rodents to reach the food, so they don't have to rely on any leftover crumbs the adults drop. I run my rat colonies 1.3 - 1.4 in them, and they can hold around 25 weanlings or 15 adults. The setup on the right are just a bunch of the early rat breeding bins resurrected to hold all the overflow
LOL... kind of funny the overflow is just about as big as the rack
Missing from the picture is also a 3'x1.5' storage bin currently housing a 1.6 colony.