Disclaimer: This is my pet theory only.
As others have pointed out, what you're really doing is creating suboptimal hatching conditions, since birds don't work like reptiles in this respect, and only some reptiles work like that anyway. But I think the idea is destined to fail anyway. Why?
In mammals, females have better survival rates in general. There are slightly more women than men on earth. Premature baby girls stand a better chance of survival than boys when all other factors are considered. Psychological disorders that cause conflict that could impact life expectancy are more common in men than women. In a drought, Cynthia Moss observed that every single male elephant calf died. So did many females, but all the survivors were female.
There are lots of reasons for these differences, but I always go back to those babies. At birth, a difference already exists.
In chickens, of course, things are flip flopped. Males have two of the same sex chromosome, ZZ, while females have ZW. My theory is that there is something stabilizing about having two of the same chromosome. That's why we see these slightly higher rates of survival in female mammals. Unfortunately, it means that those suboptimal conditions you're talking about favor males. You could go too hot, or too cool, too dry or too wet, males would still be more prevalent in the surviving chicks.
Let's face it, we don't do artificial incubation like the experts (the chickens.) We do all right, sometimes we do great, but when we don't, embryos die. When some can survive, who survives? I know that for me, when things go wrong, that's when I start to see the all cockerel hatches. I think, like male mammals, female chickens are more susceptible when things aren't just right. The male embryos are hardier and more likely to survive our attempts at incubating, as long as we don't get it too terribly wrong.
As others have pointed out, what you're really doing is creating suboptimal hatching conditions, since birds don't work like reptiles in this respect, and only some reptiles work like that anyway. But I think the idea is destined to fail anyway. Why?
In mammals, females have better survival rates in general. There are slightly more women than men on earth. Premature baby girls stand a better chance of survival than boys when all other factors are considered. Psychological disorders that cause conflict that could impact life expectancy are more common in men than women. In a drought, Cynthia Moss observed that every single male elephant calf died. So did many females, but all the survivors were female.
There are lots of reasons for these differences, but I always go back to those babies. At birth, a difference already exists.
In chickens, of course, things are flip flopped. Males have two of the same sex chromosome, ZZ, while females have ZW. My theory is that there is something stabilizing about having two of the same chromosome. That's why we see these slightly higher rates of survival in female mammals. Unfortunately, it means that those suboptimal conditions you're talking about favor males. You could go too hot, or too cool, too dry or too wet, males would still be more prevalent in the surviving chicks.
Let's face it, we don't do artificial incubation like the experts (the chickens.) We do all right, sometimes we do great, but when we don't, embryos die. When some can survive, who survives? I know that for me, when things go wrong, that's when I start to see the all cockerel hatches. I think, like male mammals, female chickens are more susceptible when things aren't just right. The male embryos are hardier and more likely to survive our attempts at incubating, as long as we don't get it too terribly wrong.
