We took the tack room in the barn which is semi insulated, with a concrete floor(soon to have a steel door due to rats chewing through it and killed about 30 chicks). I first built a large brooder box with outlets in it(an old counter from a parts store converted), then on top of it I used some recycled crates, hinges and hardware cloth to build 3 more brooders. 2 of them are 16x24 and one 32x24.Now see that is a more normal number than what you set last time. Was that a week ago? Or just a few days ago? How do you brood all those chicks? I am going to start pulling my hair out soon.
Now I have built 4 more that are 36x30(roughly) 2 of them are for 2-4 week old chick and the other 2 are for anything. Then once they start to feather we have 20 brooders in the breeze way that are converted pallets(from a local nursery). They are 40x48, these work well except when you get messy birds. We also use them for juveniles( that you are extra protective over( and roosters that can't behave. We currently have a trio of Brahma Bantams in one also. I alos have 3 that are 30x72 (2 the rabbits stole)