Artificial incubation An egg incubator. Chicken egg incubation can successfully occur artificially as well. Nearly all fertilized chicken eggs will hatch after 21 days of good conditions - 99.5 °F (37.5 °C) and around 55% relative humidity (increase to 70% in the last three days of incubation to help soften egg shell). Eggs must be turned regularly (usually three to eight times each week) during the first part of the incubation. If the eggs aren't turned, the embryo inside will stick to the shell and may hatch with physical defects. Some incubators turn the eggs automatically. This turning mimics the natural process. An incubating hen will stand up several times a day and shift the eggs around with her beak. However, if the egg is turned during the last week of incubation the chick may have difficulty settling in the correct hatching position. Anyone else see problems here.... Where do they get some of this stuff? Those humidity numbers to me are way high. High humidity the last 3 days has nothing to do with softening the shell. An turning only 3 times a week? An you stop turning the last 3 days not 7. An if all that was right then they still would have way over simplified it.