We recently built ours out of a sheet of sheetrock and duct tape - sounds hokey but so far it's been clean, warm and sturdy. Ours is 3' x 4' and 23" high. Just cut the sheet into four 23" pieces across the length of the sheet. Duct taped all the edges to keep them from disintegrating, taped the four corners together then taped all around the top and bottom. Placed wire stapled to a wood frame on the top to keep the dog and cat out. Put plastic on the floor and a good layer of woodchips with crumpled and flattened newspaper on top. Heat lamp above on a chain so that it's adjustable. Everything is working GREAT for our first attempt. The chicks all seem content and stay warm. We built a little "balance beam" to act as a perch and two have already learned how to perch on it and they're only 3 days old. We're having a blast! Hope this simple, disposable, inexpensive system might help someone. We've been happy with it.
Ken