Asphyxiation is a uniquely terrifying way to die. People who have lost their ability to feel most fear through the destruction of their amygdala still panicked under simulated drowning.

These gas chambers are almost certainly used for the same reasons the Nazis used them on people: they’re economical. The Nazis found bullets to the back of the head and mass graves to be inadequate for dealing with the sheer volume of people they wanted to murder, so they settled on the gas chambers next to furnaces because it allowed them to kill mass quantities the quickest.

There is no way of executing living animals that cannot be botched; no ethical way to kill animals bred and caged for their entire lives. The expectation of being able to have it both ways is unreasonable. No free lunches liberals.