Although like Saddam, they beat their victims with iron bars, they did not cut their heads off, slowly and with a dull blade, as their brother Arabs did, to various humans. Of course cutting their heads off, quickly and with a sharp blade, would be about as merciful as anyone ever is when killing hogs.
The humane way to slaughter pigs is to cut the arteries in the throat letting them bleed out first. It is relatively painless and unconsciousness happens rapidly, followed by death. Cutting through the trachea, on the other hand, causes breathing difficulties and momentary panic to the animal. It is not a humane method of killing.