I have used them to brood small groups of 4 to 6 six at a time. I used two hanging over a tote. I bought a temp controller to make sure it was only one when needed, a probe gives feedback at the temp. Both were 150w. This year I made a more permanent brooder with 3/4"radiant barrier...
As soon as I get everything with the coop finished, planning for a fieldtrip, and my woodshop cleaned up, I plan on posting everything plus plans for the coop or brooder including improvements.
We are going to get our first chickens this morning. I have my brooder set up and heated and I am finishing the coop this week, during my spring break. My 6 and 2-year-old are excited, and my wife asked for this as a birthday present. Either this or a shotgun, and I am thinking the shotgun...