Earlier quoted context omitted.
You might consider the other side that equal amount of animals get to be born every minute and live some lives. We usually don't consider a person being born a tragedy almost regardless of what life this person had.
Could we use this to justify factory farming humans, in that the agony and terror they experience is eclipsed by the good of them being bred into being rather than not existing at all? We would certainly have more humans being born in that case than now, is it a negative thing that we are not doing this?
We kind of do already when we romanticize life. Every human dies eventually, at equilibrium, humans die at about the rate they're born. How long the average human lives does not change that, it only changes the delay in population changes. The same is true of chickens or cows, they live shorter lives but they're born at the same rate they die. When they die has no effect on this, but whether they live is entirely dictated by their utility to human beings. So you wouldn't actually get more humans from this, just more turnover. On the same note, you wouldn't get less cows not doing it, just longer turnover, all else being the same. In actuality though, without the meat they'd be useless to us, so you would wind up with a culling and then less of them, this is not the case for humans.