From Abu Ya`la ibn Aws, may Allah be pleased with him, from the Messenger of Allah, may Allah bless him and grant him peace, there is that he said, “Allah has decreed excellence (ihsan) for everything, so when you kill, then do the killing excellently well, and when you slaughter [an animal] then perform the slaughter excellently well, and let any of you sharpen his knife and let him put the animal at ease.” Muslim narrated it.
His saying, “Allah has decreed excellence for everything.” A part of the whole quality of ihsan (excellence) in the killing of a Muslim in retaliation [for murder] is that one should acquaint oneself with the instrument of retaliation and not kill with a worn-out instrument. Similarly, one should sharpen the knife at the time of slaughtering [an animal] and give the beast ease. Nor should one cut anything from it until it is dead, nor sharpen the knife in front of it, and one should offer it water before slaughter. One should not slaughter a milking animal nor one which has a young one until it has no need of the milk. One should not be rough while milking and one should trim one’s nails at milking. The say, “One [animal] should not be slaughtered in front of the other.”
It is important to note here that the modern industrial process, driven by the insane greed and anxiety which motivates usury, does not honour any of the above courtesies of slaughter even when it is so-called ‘halal’ meat. Animals are slaughtered one in front of the other, sometimes as many as six hundred cattle in one day. They are killed while terrified, and usually after they have been given a violent jolt to the head which is supposed to ‘humanely’ stun them. Chickens on the other hand receive an electric shock the strength of which is set by the workmen. It can be set high enough to kill them before their throats are cut. Sometimes it is so strong that it will shatter their bones. The factories are full of deafening noise and angry, cursing workmen. One Muslim slaughterman whom the translator met, and who worked in a factory owned by Muslims, killed two thousand sheep on an average day, and had no real idea if he had said the name of Allah over each sheep or not. The sheep passed in front of him suspended by their hind legs and he cut their throats as they passed. Contrast that with the beauty of the slaughter by the family whose children water and feed their `Eid sheep, often for weeks on end, before it is killed in the open, in the name of Allah.
(Imam Muhyi al-Din Abu Zakariya Yahya bin Sharaf al-Nawawi, Arba`een, translated by Abdassamad Clarke and published by Ta-Ha Publishers Ltd., as The Complete Forty Hadith). In commentary of hadith no.17, p.74 -75)