I have 12 chicks in the brooder. Pretty much at the max for space and they are starting to get restless and a little fussy...They are in week 3 now and just starting to show some feather growth. Brooder is kept at a good 85*F. I set up a 150W ceramic heater bulb (no light given) double reinforced in the coop. I'm hoping that keeps it warm enough. It doesn't put off as much heat as a light bulb. Tonight is going to be 25*F, but this should be our last sub-freezing night. So I'm going to put them in tomorrow. The high temps are in the 60s and lows in the 40s for the foreseeable future. Still a little nervous!