they died during transport to the slaughterhouse or were slaughtered but deemed unsafe to eat due to a variety of reasons, including tumors, bruising, or infections.

Tl;DR the poultry industry is bad

Source: an animal rights group called Animal Equality

Seriously though, there are lots of reasons why there’s so much death, but the reasons can be summarized like this: Manufacturing cheap food at an industrial scale results in many unethical choices.

Nope the males are ground up right after sexing. In even larger numbers