Although there is no specific prohibition of stunning prior to slaughtering of animals in Islam, it remains, after certain studies, that refraining from stunning is always best, due to the following reasons.

Pain

Islam is a religion which encourages its followers to show mercy to all of creation.  It prohibits inflicting unnecessary harm to animals.  Even during time of slaughtering, the Prophet said:

“And when you slaughter, then slaughter in the most perfect of manners.” (Saheeh Muslim)

He commanded that one sharpen their knives before slaughtering.

“Sharpen your knives, so that you make it easy for the slaughtering animal.” (Saheeh Muslim)

The epitome of mercy and compassion to animals is that he said that one should never sharpen their knives in their presence, nor slaughter one animal in the presence of another.

“He commanded that we sharpen our knives and [slaughter] out of the sight of other animals.” (Ahmad)

In another narration:

“The Prophet, may the mercy and blessings of God be upon him, passed by a man who was sharpening his knife while had his foot on one side of the face of a sheep (holding it to the ground), and it  was looking up at him.  The Prophet said: ‘Couldn’t you have done this beforehand?  You wish to kill it many times.’”[1] (al-Mundhiri)

In order to be effective, CBP stunning must be performed by highly trained personnel, and specific cartridge strengths must be used.  If this is not the case, or if the pistol is not positioned correctly, the animal will have to endure the pain of being shot incorrectly, and then will have to face the pain of being shot again, or the claimed pain (although not true) of being knifed while conscious.  If the animal were to have been slaughtered without CBP, there would have been none or minimal pain felt by the animal.  In a 1996 report, the Scientific Committee of the European Commission said that, “In 5 to 10% of cattle, captive bolt stunning is not applied correctly,“ which according to VIVA (Vegetarian International Voice for Animals), translates to 230,000 cattle in the UK alone.  FAWC (Farm Animal Welfare association) reported “In the course of our slaughterhouse visits, we have frequently examined carcass heads to check the site of bolt penetration.  In our view, there were far too many cases where penetration had not been at or near the recommended position and also evidence of a considerable number of double shots (i.e. indicating that the first shot had missed its proper target).”

The same may be said for electric head-only stunning.  The Royal Society for the Prevention of Cruelty to Animals (RSPCA) says “There is increasing scientific evidence that some animals that are stunned electrically using tongs regain consciousness before they die from loss of blood.”  The reasons behind this are either an inefficient electric current being passed through the animals’ brain during stunning or the animals begin to regain consciousness if the time interval between stunning and sticking exceeds a period of 20 seconds.

VIVA explains this saying that the stun caused by the electric head-only technique lasts between 20 and 40 seconds whereas the interval between stunning and knifing is as high as 70 seconds for sheep.  This means that there are around 5 million sheep that regain consciousness after being electrically stunned before they die of blood loss.

Research done at Bristol University has also shown that after an electric stun, sheep may not be able to feel pain; they do, however, experience periods of full awareness.  Furthermore, there is no evidence that the loss of consciousness is immediate, and some people, like neurophysiologist Dr. Harold Hilman, believe that stunning is extremely painful, pointing out that the electrocution of prisoners is used as a torture method in some countries.  The animals cannot express this pain by crying out or by moving since the massive electric current paralyzes them.

Inadequate stunning also occurs in water bath stunning, especially with ducks and geese, as they tend to raise their heads when entering the water bath and their heads are therefore not fully immersed in the water.  Another problem with this method is that, although the aim of this method is to induce cardiac arrest, “many birds are improperly stunned and recover consciousness before slaughter,” according to the RSPCA.  This is also the case for sticking, as animals may regain consciousness prior to death.

The pain felt by any living being through suffocation, as in the case of gassing, is clear to any person and need not be detailed.

What can be observed is that although these methods are supposedly meant to reduce pain, the result is that the animal actually undergoes more pain, both from the initial stunning and from the following actions if stunning is performed inadequately.  Again, causing unnecessary pain to animals is prohibited in Islam.