I thought I'd share my version of the Mama heating pad brooder. I have an 8' x 8' x 6' tall outdoor brooder. I wanted a large unit to brood up to 100 chicks, maybe more if I completely lose my mind.
It is there under the straw.
A few of the 60 babies taking a mid day nap in the cave
I used a scrap of tin siding 4' x 29" and bent it into this shape
Then I taped down a reptile heat rope. I used electrical tape and made sure the rope had good contact with the tin, then I went over it again with Gorilla tape.
You need the thermostat to control the heat rope, the ability to control the temp is nice.
And covered it with foil insulation. I cut up an old ugly sweater into strips to cover the entry ways at each end.
I set it to maintain a temp of 85 on the floor in the middle. The sides are warmer and if they want more heat they just press their bodies against the tin.
I few things I have observed with this unit are:
During the heat of the day the thermostat shuts the heat element off most of the time but does not let it get below 85.
It starts coming on more often in the cool of the evening before the chicks go to bed and is all preheated by bed time. When the chicks( 60 of them) go in, the temp jumps and the unit shuts down. There is a brief period where the older ones are a bit warm and they hang their heads out the entrance. After an hour or so the temp stabilizes and the retreat back in side. I suspect that once it is fully populated it will not turn on much during the night when the weather is nice. It comes on in the early morning after the chicks vacate and is ready for them when they need to shake the morning chill. It is on the longest in the mornings.
Another thing is, so far, it has made chick integration a breeze. I have 2 wk old, 1 week old, and 2 sets of 1 day old's added over the last several days.
I just stuffed them in to the middle of the other chicks well after dark and each time they woke up like they had always been one big happy family. They wake well rested and very vigorous.
Thanks to Blooie and this thread for the inspiration and for spreading this outside the box idea that is so superior to heat lamps.
Here's to raising healthy, sane chicks.