How cold can eggs get without endangering embryo? Hen on wrong nest.

[eenie114]

We have trap nests, but I've wired them open so that I don't have to always be going out there to open them. I have a broody who got off of her nest to do the whole eat-drink-poop thing, and then she started sitting on the wrong nest because for whatever reason, the wire on her nest box was gone.

I don't know exactly how long she was off her eggs, but the eggs seemed awfully cold. I moved them back under ASAP. I candled one of them, and there does appear to be something in at least one of the eggs.
My question is, how much of a tempature drop and spike can the eggs handle? Should I just remove these eggs and give her some more to start over with? The tempature in the coop where they were is about... Say, 47-ish.
Thank you, any insight is appreciated.

 

[Debbi]

I'd stick them back under her or put them in a bator. I just hatched a Black Copper Marans chick on Easter, that came from an egg that was so cold by the time I got it, that I almost fed it to the dogs! It was probably an hour away from being frozen, but I figured what the heck, it was a nice color, so I put it in the incubator. First one to hatch, and is also the biggest chick!

 

[scooterward]

I have a broody hen that started sitting on a different egg a couple of days into it. When I found the situation, the original egg wasn't warm any more. Still, I pulled out the wrong ones and put the 'good' one back under her. Now I've been wondering if it was too long away from her. I just read about candling so I think I'll try that to see if the egg is still viable. I hope so. It's the only egg she is sitting on and the only egg from our rooster Wyatt before he went to freezer camp. Friday the 13th is the hatch date if all goes well. Hopefully she wasn't off it too long that it stopped developing.