Volume 4, Book 52, Number 309 :
Narrated by Abaya bin Rifaa
My grandfather, Rafi (radiallaahu `anhu) said, “We were in the company of the Prophet (sallallaahu `alayhi wasallam) at DhulHulaifa, and the people suffered from hunger. We got some camels and sheep (as booty) and the Prophet (sallallaahu `alayhi wasallam) was still behind the people. They hurried and put the cooking pots on the fire. (When he came) he ordered that the cooking pots should be upset and then he distributed the booty (amongst the people) regarding ten sheep as equal to one camel then a camel fled and the people chased it till they got tired, as they had a few horses (for chasing it). So a man threw an arrow at it and caused it to stop (with Allah’s Permission). On that the Prophet (sallallaahu `alayhi wasallam) said, ‘Some of these animals behave like wild beasts, so, if any animal flee from you, deal with it in the same way.” My grandfather asked (the Prophet (sallallaahu `alayhi wasallam)), “We hope (or are afraid) that we may meet the enemy tomorrow and we have no knives. Can we slaughter our animals with canes?” Allah’s Apostle (sallallaahu `alayhi wasallam) replied, “If the instrument used for killing causes the animal to bleed profusely and if Allah’s Name is mentioned on killing it, then eat its meat (i.e. it is lawful) but won’t use a tooth or a nail and I am telling you the reason: A tooth is a bone (and slaughtering with a bone is forbidden ), and a nail is the slaughtering instrument of the Ethiopians.”
In a past post, the proper Islamic etiquette of slaughtering an animal was discussed in detail, from saying Bismillah in the beginning to sharpening the blade and being kind to the animal. This hadith discusses the “instrument” used to slaughter the animal. It’s apparent and obvious that bones and nails are prohibited. And whatever is used other than that must cause the animal to bleed profusely.
Having said that, there’s a lot of confusion about saying Bismillah when using modern methods (i.e. machines) to slaughter chickens, whether to say it every time a chicken is slaughtered or to say it once before turning on the machine. A question is recorded in Fataawa al-Lajnah ad-Daa’imah:
Is it permissible to say “Bismillah” when operating the machine which does one repeated movement. Please note that what is meant is saying “Bismillah” only once, when starting the machine for slaughter.
Answer: it is acceptable for the person who is operating the machine to say “Bismillah” once when starting it for a number of (chickens) with the intention of slaughtering them, so long as the one who is operating it is a Muslim or a Jew or a Christian.
‘Abdullah ibn Ghadyaan, ‘Abd ar-Razaaq ‘Afeefi, ‘Abd al-‘Azeez ibn ‘Abdullah ibn Baaz. End quote.
More about stunning animals, saying Bismillah once or repeatedly and other related discussion here.