I finally found the best tubs to make into duckling brooders for my ducklings that are off heat at room temperature. I initially use heating pads under tubs and they help keep the ducklings dry because they dry out the spilled water and poop on the shelf liners but I have been having trouble keeping things clean and dry once I move the ducklings off of heat and keep them at room temperature before they go outside. Now I have found the perfect solution. I found some Sterlite tubs with black handles that are 32"x18" and 14" tall, then I added black hard plastic liners that are sold as door mats at Home Depot (the tubs came from Home Depot too so I was able to find a perfect fit while in the store). The mats are rigid and they fit perfectly inside the tubs, which have a deep well around the edges. The holes are nice and deep but they are a bit big so I got a package of material that is similar to shelf liners but made to keep rugs from slipping and I cut them to size. The package I got was supposed to be 4'x6' so I figured I could cut six pieces that measured 16"x32" but they ended up being a bit narrower than that because the sheet was not cut square and I had to cut it square before I could measure it, which ended up creating a bunch of waste I had not anticipated. I had thought the liner would completely cover the mat but it covers well enough that the ducklings' feet are protected from slipping down into the holes. All the poop goes through the liner and the mat to the bottom of the tub while the ducklings have a dry surface (nothing is ever clean for long with ducklings) to walk on. I am using three tubs stacked so I just slide the lids back enough to vent them and hold the tub above. I bought six tubs total so I can put fewer ducklings per tub or have clean tubs to move them to instead of cleaning the tubs while they take their bath. The new tubs can go two days before they need to be cleaned with about a dozen ducklings per tub and they clean easily. The liners are getting stained and they are the hardest to clean but I can replace them periodically like I do with the shelf liners.