I know the rule of thumb for chicks to hatch from under a broody hen is 21 days. I've read about hens leaving the nest for hours, sometimes all day and they'd still hatch. I read someone said it was 12 degrees and their eggs was very cold, but they still hatched.
Another thing of interest I read was to do with the hatch being prolong because of absence from the nest. We know that a broody hen will "take care of her business" but these weren't the case. Folks seem to think that if the hen has been off the nest for a total of X number of hours then you can add X number of hours to the hatch date.
That being said, this is day 27 and the eggs don't stink so I'm wondering if all is well. I haven't candled them. Has anyone had this many days pass and they still hatched? Yes, they are fertile. Yes, I put them under her all at once on the same day.