Our brooder box is stored in six (relatively) flat pieces: the base/floor, four side walls, and the screen top. The entire design grew from an old window frame found at the curb. Using hardware cloth as a screen, the window frame is the top of the box. The hardware cloth is sturdy enough to keep out our cats and hold up the heat lamps.
The base/floor of the box is covered with cheap vinyl squares, making clean up easier than scrubbing a rough plywood base. In the photos, you can see the 1x2 wood frame in the corners and around the top perimeter. The design is easy to screw together now and unscrew for storage later. Be sure to keep the screws properly labeled in a container during the off season.
It's much too cold in the garage right now, so the chicks will begin their lives in the basement. They're adorable at first, but soon begin to toss around their bedding materials. It's a dusty mess. Don't say I didn't warn you.
Tomorrow we'll add the heat lamps and thermometer. We need to get it around 90 degrees before the arrival of the babies on Monday. We're nearly ready!