Hello Adam. i do keep a quad of rats in apprx 36 x 18 x 18 breeder all glass w. wire top and use quart glass beer bottle with screw on sipper that go rite thru a 4" hole in the wire and elec taped a stopper around the bottle made from vinyl tubing and black tape,and a long drop food hopper(cylindrical).
And a dust pan makes quick work of changing the substrate.L8r Chris aka farfrompukin....LOL