I’m not sure what you mean by “factory-farmed,” but cows, sheep, pigs and free-range chickens seem healthy and vigorous. I’ve never been inside a battery-farm or a veal pen, but I’ll grant arguendo that those animals aren’t healthy or vigorous. But that’s an argument for eating free-range chicken, not for vegetarianism.
I’m not sure what you mean by “factory-farmed,” but cows, sheep, pigs and free-range chickens seem healthy and vigorous. I’ve never been inside a battery-farm or a veal pen, but I’ll grant arguendo that those animals aren’t healthy or vigorous. But that’s an argument for eating free-range chicken, not for vegetarianism.