Improvements: bury the barrel up to 6 inches from top, fill the barrel halfway with dirt and straw. Create multiple short tunnels leading in and between the barrels then lightly fill each with dirt so that the does can dig around and feel like they are creating their own nests. Cover the tops of each barrel with a removable rabbit friendly flower bed so that it looks and feels like a real warren.
Each hole is 24x24 The cages themselves hang from the PVC which allows the sides to extend further from the walls of the cages. The pans are made from wood, covered in a heavy gauge plastic to protect them. They are a single pan per level to keep rabbits from peeing in between trays onto rabbits below. They are attached by drawer slides. To clean them I just pull out the "drawer" lift out puppy pads, wipe down the plastic, replace the puppy pads or incontinence pads.