microwavable heat pad in nest box?

[FoxyChicken]

Hi all,
I'm just wondering if anybody has tried one of these microwave heat pads in their nest boxes to keep eggs from freezing? I only have one chicken that lays her egg before I leave for work, so all of the other eggs have to sit in the nest box all day until I come home. With winter coming on in Northern Minnesota I'm starting to get a little worried about frozen eggs! These say they hold heat for up to 12 hours, but I'd be surprised if that were true, especially on a -40* day. If it could even hold it for 8 hours I'd be happy.
So has anyone out there tried this? How did it work? (I'm looking for a solution that doesn't require electricity)

 

[ChickenCanoe]

I don't know what they cost but it would be worth a try.
I used an aquarium heater for a couple of years that helped a little. The kind that stick to the bottom of the aquarium.

 

[donrae]

If I were in your area I'd give it a try. But, not that fleecy cover, that just looks like a mess waiting to happen! Find something washable to put it in.

 

[FoxyChicken]

Thanks for the replies folks! It's only $27 so I figure I'll try one and if it seems to be holding its heat I'll get another for the second nest box. Good suggestion on the fleece cover, maybe I'll just put an old towel over it instead.
I'll report back on how it works after we get some bitterly cold days if anybody is interested!

 

[ChickenCanoe]

They have those stretchy nylon book covers that should do the trick.

 

[aart]

I would definitely be interested to hear how it works!