In response to the incubation and candling comments and questions:
I usually start my eggs out at 35% humidity and let it fall to 20%, then add about a tablespoon of water to bump it up to at least 30% and let it fall again. That works for me to get the air cell to a correct size. I candle at 7 days and 14 days and if the air cell looks too big or too small I adjust the humidity to get it right before hatch. I had to keep adding water this time because the air cells were shrinking too fast in the
Brinsea and the humidity was down as low as 10%.
Last year was my first year hatching and I was a paranoid new hatcher. Then I watched my broody hens and decided that eggs were pretty tough.
The first hatch this year was a single goose egg I rescued from freezing and a dozen duck eggs I threw in to keep it company. The goose egg quit halfway through, but I hatched out 3 muscovies and 5 pekins. Most of the other eggs were clear or early quitters. I took the top off the incubator for 15 minutes a day to let them cool and sprayed them with water. All but two hatched with no help and the two I assisted were so big they couldn't move. All are doing well.
Also hatched 4 out of 15 shipped eggs and 10 out of 13 mixed LF cochin eggs from my own flock. Yesterday I hatched 6 out of a dozen turkey eggs.
I mention this because the turkey eggs were the first laid by the flock and the poor eggs were so abused. I thought they were goners and only left them in the
Brinsea so I could fiddle with the temperature and try to get it to regulate. Those poor eggs were candled every day, they got chilled, overheated, handled like they were dead, and when I decided to check one last time, one of them waved at me and I left them all in to preserve the heat sink and keep the temperature regular. Imagine my surprise when six hatched.
The lesson here? If the egg is a solid dark mass with a decent sized air cell, don't give up. I retreat to my closet during the day with the eggs in a carton and candle with two of those little metal LED flashlights, one at each end. I turn the egg willy-nilly to get a view from every direction so I can be sure what I am seeing. My hens are not very careful with their eggs as far as kicking them all over and rolling them back in, especially when another hen moves in to lay a fresh egg. Some of them are off the nest for quite a while, so I figured I would just pretend to be a mother hen and stop treating them as super fragile. My biggest concern is cooking them if the temp spikes too high.