The bigger ones run away. Combines are enormous and noisy. They don't sneak up on you.
But I think intent makes a difference.
Mice killed by farm equipment are accidental side effects with some ethical implications which most of us choose ignore.
Livestock raised for slaughter is a different ethical question entirely.
(Meat eater here. I do find it to be the natural order of things, but I am aware that I could justify slavery and sexual exploitation by the same logic, and that makes me pretty sure I'm giving myself a pass on the meat thing.)
Yeah, I'm with ya on the combine. But, farmers shoot or exterminate animals like deer, gophers and pigs that threaten their crops. It seems as though it's necessary to kill animals in order to provide even a vegan diet to the world's population, and I often see this truth being ignored by absolutists -- which seems to be what the original comment about combines was reaching for.
I eat meat, too. I'm... mostly okay with that. But I'm told that pigs are smarter than cats, and that makes me a bit squeamish. Natural order sure is a slippery slope. It is human nature, I hope, to aim to be better than our nature.