How to keep the eggs from freezing?

[Swesey Hollow]

My 5 hens all lay in the same little hutch area, despite the fact that I made 5 separate laying compartments. I am thinking about either one of those reptile heaters or encasing a some 10 watt 10 ohm resistors wired in series in a small cement pad and putting it under the straw. Either one would prevent the eggs from freezing. Neither would be any warmer than about 40 to 60 degrees, so fire shouldn't be an issue.
The resistors are available at Radio Shack, two for $1.21. Four encased in an 8" x 8" x 3/4" cement pad should do it: http://www.radioshack.com/product/index.jsp?productId=12566075&locale=en_US
Here is a link to a heater pad:
http://www.ebay.com/itm/Adjustable-...557?pt=LH_DefaultDomain_0&hash=item2a210db3cd
Did anyone ever try this?

 

[Swesey Hollow]

My 5 hens all lay in the same little hutch area, despite the fact that I made 5 separate laying compartments. I am thinking about either one of those reptile heaters or encasing a some 10 watt 10 ohm resistors wired in series in a small cement pad and putting it under the straw. Either one would prevent the eggs from freezing. Neither would be any warmer than about 40 to 60 degrees, so fire shouldn't be an issue.
The resistors are available at Radio Shack, two for $1.21. Four encased in an 8" x 8" x 3/4" cement pad should do it.
Heater pads are available at any pet store.
Did anyone ever try this?