Apologies if this isn't appropriate for this SE - it was the most relevant one I could find.
When animals are being led to slaughter, I imagine it must happen occasionally that one gets the sense that something is wrong—perhaps they hear or smell something unnerving up ahead—and spooks. Whether fight, flight or freeze, this will presumably interrupt the process and their behaviour may potentially spook additional animals.
What happens in this situation? If an animal flat-out refuses to move/will not respond to attempts to calm it, do the slaughterhouse workers just euthanise it on the spot and move on? Or would this just spook the surrounding animals more? Does the stress-induced lactic acid buildup mean that the animal is not processed for food?