A picture of a home built rabbit cage

This picture show what the 12" urine guard is for in the material list. the left side of the cage-front has a feeder on it, this keeps rabbit rear ends away from the front of the cage (except when they are very young) and therefore most poo and pee from coming out the front.

The right side is where the watter bottle (or bottles with a growing litter) will go. In addition to controllin g the rabbit pee, this has the added benefit of keeping all the water dribbles in the cage and into the pan and off the walkway.
These cages are stacked 3 high using leg kits.
I prefer the galvanized urine guards. I can't imagine using the plastic ones, my rabbits would tear them up in a day.