I was looking up why I might have had so many hens hatch this year in comparison to roosters. If I could figure that out I would repeat the process next year. This is what I found.
A study done in Australia (Australian Journal of Agricultural Research) has shown that eggs stored at 40 degrees Fahrenheit rather than the recommended 60 degrees will hatch out more females. The ratio of female to male eggs does not change. What changes is the colder temperatures kills off more of the male embryos than female.
I gathered eggs a bit all day and tucked them under the hens so how much they chilled I don't know. The only thing I can figure is that the hens were all young and therefore inexperienced. My ratio of eggs under the hen and those that hatched was not nearly as good as my friends who has old, old hens. That might have caused some of the eggs to not be turned as well or not rotated in placement under her as often as they should have and caused chilling of the eggs. Whatever the reason, I hope we get as good a hen crop next year. I hear the coyotes a howling nor far behind the barn tonight as I tucked in the stock. Yes, we will need replacements if this predatory problem continues.