The steel cover on the floor brooder was leftover from a pole barn. It originally worked off a wafer thermostat, but now the Lux thermostat regulates it. The heating element was a clearance item at TSC, years ago, designed to keep livestock water tanks from freezing. I put a welded wire cage around the element to protect the birds. There is a low watt LED to attack the chicks and shed some light. Now days they suggest blue lights for growing birds, but the red one works.
Note I place the brooder close to the wall so the small chicks can come and go, but the bigger ones generally avoid the tight space.