Oh I should point out it was my neighbor down the road's eggs I used that were refrigerated. He gets way over 55% rooster chicks when he lets his broodies do the job. But on the refrigerated eggs I got I only hatched the 1 rooster to 8 hen chicks. I had high mortality in the eggs but I attributed that at first to the fact they had been refrigerated. It was only as I thought more and more about it that it occurred to me that it might have to do with the temperatures so I looked around on the internet and found some studies.