This isn't anything new. It's been going on for ages. They don't need the males, so they're killed. Sadly that's what happens. If you don't want it to happen, don't eat eggs or chicken.
It happens in other commercial animal breeding too. Females are more prized than males due to breeding. You only need one or two males, take a sample, and then breed as many females as you want.
That sort of thing even happens without human intervention. Male spiders get killed after breeding. There's a mouse species where the male dies after mating with as many females as he can....kinda depressing.
Is this on okay video to have on the forum? You know, just in case younger members see.... :/