Short answer
Islamic slaughter is designed to reduce suffering: a very sharp knife, one swift cut to the throat, no sharpening the blade in front of the animal, and no skinning until it has died. Cruelty in any slaughterhouse, halal or not, is a sin in Islam. Scientists still debate how much pain different methods cause.
Slaughter with a sharp blade and a swift cut is required by the Sunnah, and anything that adds to the animal's suffering, such as a blunt knife, sharpening it in front of the animal, slaughtering one animal in sight of another, or cutting before it has died, is makruh.
The four schools agree on this.
Explanation
The Prophet ﷺ said that Allah has prescribed excellence in everything, and when you slaughter, slaughter well: sharpen your blade and spare the animal suffering. The scholars built on this a list of rules that every school teaches:
- use a very sharp knife and cut quickly, in one motion where possible;
- cut the throat so the main blood vessels are severed and the blood drains fast;
- do not sharpen the knife in front of the animal, and do not slaughter one animal in front of another;
- give the animal water, handle it gently and do not drag it;
- do not break its neck, skin it or cut it up until it has fully died.
A fast, deep cut makes blood pressure to the brain fall quickly, and the animal loses consciousness. Critics argue that stunning first is kinder; supporters of slaughter without stunning point to problems with failed stunning. Researchers disagree, and the result depends heavily on the skill of the slaughterer. AmalKit does not take sides on the science, but the Islamic rules are clear that needless pain is forbidden.
Islamic law treats cruelty to animals as a sin in its own right. Rough handling, overcrowding and careless killing in a plant that calls itself halal are against the Sunnah, even if the meat is technically lawful. Muslims have good reason to ask suppliers about welfare as well as method.
Whether meat from stunned animals is halal is a separate question (see stunned meat). For the conditions of halal slaughter, see what makes meat halal.
The evidence
Quran, Surah Al-Hajj 22:37
لَن يَنَالَ ٱللَّهَ لُحُومُهَا وَلَا دِمَآؤُهَا وَلَٰكِن يَنَالُهُ ٱلتَّقْوَىٰ مِنكُمْ ۚ كَذَٰلِكَ سَخَّرَهَا لَكُمْ لِتُكَبِّرُوا۟ ٱللَّهَ عَلَىٰ مَا هَدَىٰكُمْ ۗ وَبَشِّرِ ٱلْمُحْسِنِينَ ﴿٣٧﴾
Their meat will not reach Allah, nor will their blood, but what reaches Him is piety from you. Thus have We subjected them to you that you may glorify Allah for that [to] which He has guided you; and give good tidings to the doers of good.
Slaughter is an act of worship judged by the conduct behind it.
Sahih Muslim 1955
Sahih... إن الله كتب الإحسان على كل شيء ...
"Allah has prescribed excellence in everything."
The basis for every rule of mercy in slaughter.
Sunan Abi Dawud 2815
Grading to be checked... وليحد أحدكم شفرته وليرح ذبيحته ...
"Let each of you sharpen his blade and spare his animal suffering."
Commands a sharp blade and sparing the animal pain.
Where the ruling is recorded
- al-Hidaya, Kitab al-Dhaba'ih. What is disliked in slaughter because it adds to the animal's pain.
- Bada'i al-Sana'i, Kitab al-Dhaba'ih wa al-Suyud. The sunnahs and disliked acts of slaughter.
Checked by our team. For a more accurate answer to your own situation, consult a scholar. Quran translation by Sahih International. Hadith Arabic from the standard editions of the six books and the Muwatta, with gradings as recorded there; the English is our own rendering. Spotted a mistake? Tell us.