Animals have it better on a farm, even if they are killed than they would have in the wild. So therefore it is ethical to farm them.
This is specifically to address the justification based on: "Animals in the wild suffer. Animals on farms suffer less. Therefore farming animals is ethical", and is related to the argument addressed elsewhere that "Farm animals would die if we released them into the wild".
One can hardly consider standing in one's own filth for hours on end until meeting an untimely demise to be somehow better than in the wild. Depending on the animal, conditions in the wild are not bad at all and conditions in factory farms are, by comparison, abysmal.
One common defense is "But I'm just talking about well-treated animals", but it would seem as though relatively few carnists eat completely vegan at restaurants and any other situation where they cannot ethically source the animal products they consume, so it would seem as though this isn't the actual justification carnists are relying on for their actions.
Those aren't the only two options. The third option is to not breed the animal into existence. It's a false dichotomy to say that a cow would die in the wild because that cow simply would not exist, which is far more ethical a situation than bringing one into existence just to imprison, torture, and slaughter it for one's own entertainment.
"Better" isn't "good". Even if we accept the premise of the claim, it's not a reasonable argument to compare something bad to something worse as a means of making the slightly better thing somehow ethical. "Bad" is bad; "better but still bad" is also bad. We can compare absolutely any bad act to something arbitrarily worse as justification, but no reasonable ethical system grants a pass on that basis.
Moral nihilism is the only place this argument can run, which is to say "There is so much suffering with animals dying in the wild, factory farms are almost inconsequential and therefore morality has no meaning", to which the answer is 1) That is factually inaccurate, there's far more animal agriculture than wild land animals and 2) even if it weren't, moral nihilism itself is a poor argument.