The only way to sex eggs is an invasive procedure that requires the removal of some shell once incubation has begun and testing for a particular hormone. It's called 'in-ovo' sexing. Male eggs are then terminated (rather than terminating them at hatch), creating only females for the egg laying industry. It's a complex procedure that requires laboratory conditions. https://en.wikipedia.org/wiki/In-ov...farming, in-ovo,by emerging from its eggshell).
It's supposedly more humane.
Birds are descended from dinosaurs which are actually quite different to reptiles, and the family of dinosaurs that birds descended from were also unique as far as dinosaurs were concerned. Birds are able to regulate their own temperature (as dinosaurs were). They don't have to rely on their environment as lizards do. Not all reptiles use temperature to determine the sex of their offspring, but those that do actually don't have X and Y chromosomes per se. Birds do, though theirs are represented as W and Z (males are WW, females are WZ). Interestingly the sex of snakes are also represented in the same way as birds are, as snakes do not have temperature reliant sex determination. Some reptiles actually utilise both systems so they are sort of an evolutionary link. This article explains it clearly if that's something you are interested in: https://www.scientificamerican.com/...case—which governs,the heterogametic sex (ZW).
It's supposedly more humane.
Birds are descended from dinosaurs which are actually quite different to reptiles, and the family of dinosaurs that birds descended from were also unique as far as dinosaurs were concerned. Birds are able to regulate their own temperature (as dinosaurs were). They don't have to rely on their environment as lizards do. Not all reptiles use temperature to determine the sex of their offspring, but those that do actually don't have X and Y chromosomes per se. Birds do, though theirs are represented as W and Z (males are WW, females are WZ). Interestingly the sex of snakes are also represented in the same way as birds are, as snakes do not have temperature reliant sex determination. Some reptiles actually utilise both systems so they are sort of an evolutionary link. This article explains it clearly if that's something you are interested in: https://www.scientificamerican.com/...case—which governs,the heterogametic sex (ZW).
