Yes, Thermocubes. They provide two outlets so you plug two lamps or even more with a three way plugged into it. They "turn" the power on at 35 degrees and off at 45 degrees. They are inexpensive also, usually run arount $18 dollars. I find them very useful. Saves me from having to go out and plug and unplug heat sources every day. The only thing I wish was better was that they would turn off at maybe 40 instead of 45 degrees.
I use one of the thermo cube type thermostats in my main hen house to turn on and off the water heater. Thats it. We frequently get to 0* F during the winter and they do just fine without heat.
I brood my chicks outside in a small brooder coop. This coop is about 4 X 3 (floor space) and is in an 8 X 24 run, which is also covered in netting. Inside the brooder coop I have a heat lamp, that is plugged in to an adjustable thermostat. As the chicks get older I turn the temperature down gradually. I also have a remote wireless thermometer. The sending unit is inside the brooder coop and the readout unit is mounted to the outside of the brooder coop. Works slick. The heaqt lamp doesn't stay on all the time, which saves me money and the chicks get used to ambient temperature. Chicks are much more tolerant of temperatures than most give them credit for.
If you really want to heat your layer's coop, I would suggest one of the adjustable thermostats. But, like has been said previousy, they dont really need it.
Extra lighting during the shorter days is the main thing in steady winter egg production. That being said, my personal philosphy is that it is good for the hens to slow down a little in the winter, and not produce as many eggs. This allows them to use the energy to stay warm, and I believe, is part of the natural cycle for egg laying. The hens that don't get supplimental lighting can end up laying for more seasons than those who get supplimental lighting and keep on cranking out the eggs during the winter. Just my 2 cents worth. I say let them take a short break.
Some breeds also lay better in the winter than others. Even within the breed there are variances. Last winter my daily egg production slowed, and during January was about 1/2 of what it had been in November. But it picked back up in Feb and March.