How long can less than 2 day old chicken embryo survive without ideal heat for hatching chicken eggs

[Luckybaby]

There was a heavy rain two days ago for a short period of time. Unfortunately, one of my broody hen laid it's egg, where rain drops will directly drop on it's eggs if it rained. I put an umbrella, but I was too late to prevent any water from reaching the egg. The following day, she left her eggs from morning until twilight and she did it again on the following day. I forced her to sit on her eggs on the time she is about to sleep for the night, during those 2 days. I think she only incubated the eggs consistently for one day(doesn't include the time when she gets out to eat and make poop for about 30 minutes). It was on the next two days, where it left the eggs most of the time, when the sun on the sky is visible to the naked eye. I put about 12 inch x 12 inch aluminum foil on the top of her nest two days ago, and now, she is incubating them consistently since last night. If the embryo is in between 24-48 hours old, can it survive without ideal temperature for hatching eggs for about 10 hours for two consecutive days?

 

[BlueEggsDaily]

Interesting that she didn't want to sit on her egg the first couple days. I would hope and suspect that as she continues to sit on the egg from here on out the chick should be fine-
Good luck on that and I hope you will have a baby chick!!

 

[Luckybaby]

I candled it about 1 1/2 hours ago, and I saw veins and the embryo. I wonder how long can very young chicken embryo survive on high 70's and low 80's temperature?