I haven't read all the suggestions but would like to throw in my 2 cents. For years now we use 2 gallon food safe buckets with horizontal nipples on top of cookie tins with a light kit inside. That is on a plastic crate for the adults, and shorter blocks for younger ones. I useually use 40 watt bulbs but in December and January when we get those arctic blasts we put in 60 watt bulbs and always have an extra in each tin. This year I put a 5 gallon bucket with horizontal nipples in the big covered run with all the pullets. We put insulation tape with black duct tape over it around the bucket and an insulated top. Since it is outside when it got really cold the 60 watt kept most of the water thawed, and since a little bit of ice was on top I put in a 75 watt bulb.Very eaasy, cheap, and works great.