The roller coaster weather plays havoc on fertility on eggs. Too chilled an egg just isn't the best environment for an embryo. I've stopped collecting from the outside pens during these temps. If I found a hen on an egg in the outside pens, I was collecting it and marking it "cold". Often when I candle those are not making it to 10 days. So only those eggs from the inside pens are making it to the egg turner until this weather settles.
Next week with the temps in the 70s might help.some outside pens for a short time.
I've heard that frostbite on combs will affect the cock bird's fertility. But, I haven't read any research on that.
Greenbeetle, please notify the thread leader on the auction about your eggs if you bought them on the online BYC auction. If the eggs were not fertile, she is keeping records on those who ship out bad eggs.
I have two Delaware Bantam hens in an inside pen that are hatching eggs. Yesterday there were two already dry. One had gotten out of the nest and the new moms didn't know to call it back so it perished. The dry baby is inside with another chick in the brooder . I will check several times today, bring in the babies, keep them warm and then take them back to the moms when they are strong enough to hop back in the nest. When babies are the size of an English walnut, the cold gets them quick.