Wanted to join in thes conversation since I had a rooster/hen ratio problem myself this year. I was wondering if incubation temperature had anything to do with hatching more roosters. It does with reptiles such as lizards and alligators... the higher temps hatch more males and we had a temperature spike while incubating. My other theory was that my new rooster is responsible for shooting out too many male sperm or something. What if I tried a different rooster for fertilization?
By the way, out of 23 eggs, we got 13 roosters. That's only 65% roos, which I thought was horrible - I see others have done worse. Last year we hatched 10% rooster to 90%hens but it was not the same rooster doing the fertilization and we didn't have the temperature spike.