To understand why the US breeds are different to other countries, have a read of: https://www.nationalgeographic.com/environment/future-of-food/poultry-food-pr

To understand why the US breeds are different to other countries, have a read of: https://www.nationalgeographic.com/environment/future-of-food/poultry-food-production-agriculture-mckenna/ https://www.nationalgeographic.com/environment/future-of-foo... It describes a competition to breed large breasted chickens in the US, post WW2. The downside to that larger breasts is a decrease in flavour.