Commercial Chick Brooder towers require a 48” footprint.  Not everyone has that much space.  This 36”x18” shelving unit can accommodate 5 Hefty hi-rise under-bed storage totes, which are the only totes that can handle a PINT mason jar waterer.  Wayfair does not sell extra shelves, but Trinityii.com, the maker, does.  Drill 1” ventilation holes on either side, plus one at the end for power cords from the 12x12 brooder plates.  My birds prefer this over boxes with heat lamps.  Plus it’s a lot more attractive.   These shelves were VERY easy to assemble.