As someone who grew up in the country where my family (that was kinda poor when I was born) bred the animals we ate, I remember that businesses selling eggs also sold male chicks to the local farmers and only kept the females to make eggs

We had a few chickens who layed eggs and we ate the rest of them

My grandparents bought male chicks from said businesses because the ones hatching from the eggs were not enough to sustain a quite large family

You had to go there to buy them, so I don't think it was very costly

The logistics of killing the males and shipping the meat to companies making animal food is not more convenient (IMO) unless animal food is more profitable than human food, I don't know about it, but I hope it's not the case and it's not the main motivation behind it.

The point of not killing the male chicks I imagine is to show kindness towards animals, selling them (or selling the male eggs) to someone who could make food out of it, I think should be considered equally good, if not more.