I built my Mama Heat Pad today. I started with a frame made from 1/2" hardware cloth cut to the dimensions of the pad - 12"x24" and then bent it into the cave shape. It is 6" high in the front and 3" high in the back. It was a real bear getting it to sit flat thought, it kept wanting to warp. But I finally got it to sit reasonably level.
Here's the frame inside the brooder with the pad on top. I didn't have any plastic, so I covered it with a couple layers of paper towel and wheat grass bedding for now.
I then replaced the heat lamp with a red LED bulb, although the color doesn't show because of the flash. This is just for lighting to create a day-night cycle, I don't want to have to burn the garage ceiling lights all day. It is controlled by a small appliance timer, so it will turn on automatically at 7AM and back off at 7 at night. (see upper right).
It took a while to get them to realize the new cave wasn't something they needed to be afraid of. Now if I can get them to realize they're supposed to sleep inside of it instead of on the top!
They're going to get along real good with the rest of my flock - they all prefer to sleep on the roof (of their coop) instead of inside as well!
EDIT: I put a thermometer about halfway inside the cave and after an hour it has stabilized at a smidge over 80 F, which seems to be their comfort zone based on their behavior with the heat lamp.
Edited by FlyWheel - 4/7/16 at 3:41pm