Peter Singer is 'the godfather of animal rights' or whatever and he has a metric for ethical chicken farming, like a certain number of chickens raised per acre, free range.
It's way fewer chickens than currently raised but I think that's an interesting way to think about it...if we didn't have demand for eating chicken, many of these chickens wouldn't exist. Is that better than living a close-enough approximation of your wild life? Kind of a hard question.
It's not that any life is better than nothing, it's that a good-enough life is better than nothing, and there has to be some level at which it can be said a chicken had a good-enough life.
Obviously he doesn't think factory farm chicken lives are worth living, but he thinks there is a possible chicken life that is.
We actually do make this calculation for humans. A lot of countries traditionally get abortions if a fetus has down syndrome, that is a decision saying that life is not worth living. The US doesn't do that as much but there are conversations around euthanasia, that's the same idea but for humans. There is a level of a good-enough life and we weigh life and death decisions around that.
I think the real argument against this is just that the whole idea doesn't track and killing any animal for sustenance when you don't have to is just wrong at the core. THAT is where I disagree, but I can't math my way into changing your mind on it because I'm accounting for the quality of life for potential future beings, and you're just not. I don't think there's a "right" way to account for that inherently.