Nice link, Cowpoke. In the big commercial incubators where they might have 60,000 eggs in one incubator, that number of eggs generate so much heat late in incubation that the problem is more of getting rid of the excess heat instead of having to heat the eggs, especially in the middle. The eggs generating their own heat is part of why I don't worry about a broody being off the nest for a while or an incubator losing power for a while, especially late in incubation even if I don't have 60,000 eggs in there. Getting excited and doing something dramatic isn't likely going to help and it's usually not a big deal anyway unless something really extreme happened.