I started mine in a plastic bin. Then I ordered the plans for a pallet coop - very simple design. It is hot here in Florida so they went out week two. There were 20 in that lot so they definately outgrew the brooder in minutes. That big pallet coop has been great except now they all want to roost on the highest roost. So I need to add another roost. Actually, I need to sell a few and build another pallet coop. The good thing about the pallet coop was that the materials were FREE and the plans cost about 12.50. We find free pallets EVERY WHERE and My husband is obsessed with getting more. I finally got the chicks I wanted to get a long time ago - the 20 was a weak moment. I shouldn't have done it but I did it and I don't regret it but 20 was a TON of chicks and more than I had planned.
Check out the coop section because you will be surprised what people have built and in the summer with good weather - you can keep the chicks warm without electricity - actually keeping them cool is the concern.
Caroline