I'd read something on this before but wasn't sure if the higher temp makes a girl or a boy. I incubated 23 silkie eggs in 2007, 19 hatched and 17 would be cockerels. I think maybe temperature at incubation might've been a factor?
Nope.... Birds aren't like reptiles that way. The sex of mammals is determined immediately upon fertilization. A result like yours must have been due to genetics. That's a large percentage that hatched... and say they all hatched and the rest were female.. that would be 17 males and 6 females. 75% male to 25% female. A more normal ratio would be 50%/50%. If you don't want yet more Roos, maybe you shouldn't let them fertilize anything?
No not what you said.....birds aren't like reptile.......but BIRDS ARE NOT MAMMALS.....unless they have fur(hair).....no biggie didn't see where you said birds sex was at fertilization..........
My understanding is unlike mammals. The female (hen) determines the sex at fertilization. I've heard so many wives tales about how to get more hens than roos but it's ultimately going to be whatever the hen produces. I did hear somewhere that the ph level in their drinking water could affect the sex ratio however I'd think if anythings been scientifically proven we'd have heard about it by now.
I read recently, (I think on this forum) of someone doing a study to determine if feeding sorghum increases the ratio of pullets. One would have to raise a lot of fowl to have a significant sample size.