If you end up having to go the cardboard route, I've seen some brooders made of the octagonal cardboard bins that grocery stores get watermelons, pumpkins, etc. in. With a heavyweight tarp as a floor. I use a wood/netting brooder with a tarp floor, unless I only have a very small number and then I use a large rubbermaid tote.I need some ideas on a bigger brooder? I have the largest container I can find locally and in another week or so I'm going to need to upgrade, I was going to use a 6ft kiddie pool but that just seems so short....hmm. I dont want to make one out of wood, but does anyone else have any off the wall ideas rather than just a big box? Also for those that DO use giant boxes where is the best place to look you've found?