Most of the people I know who raise chickens cull the extra roosters and older hens at least annually. It just makes good economic sense not to keep feeding animals that aren't producing something of value.

So far, when I have culled, I have sold off the extras rather than slaughtering them, but as we want to include chicken meat in our and our animals' regular diet, eventually I'm going to have to learn to slaughter them humanely, which I'm not looking forward to doing.

But I know, given my deep and lifelong love for animals, that I'll take far greater care to do so as kindly as possible, which most will not. Having majored in biology, and knowing a fair amount about their bodily morphology, will help as well.