viability question

[SLWyandotte]

how cold can an egg get and still be viable? the chickens have a heat lamp above their perch but the nest boxes are on the other end of the coop. some of my girls lay a bit late and i gather their eggs in the morning. it is getting down into the 30's here at night. i know the eggs that freeze solid are no good for hatching but what is the cut off temp. i know it's probably not an exact science, but a rule of thumb for a sustained temp would be nice so i don't try to sit a bunch of eggs that will never hatch.

 

[oldorchardfarms]

When the egg is laid it should be around 105 degrees, with the cold you should try to collect eggs as often as possible they should be stored at 50-60 degrees, i dont know exactly how cold will make them no good but I collect morning and night and all of my babys are developing great, and we have already had snow fall