This link is from the site of an Halal organic butcher company in the UK:
Abraham natural produce. Providing the electric stun is calculated just right, the animal will be rendered unconscious for a short period, during which time the throat is cut. According to Islamic law, this is perfectly acceptable for Halal, and imho, an excellent compromise. There is absolutely nothing in the Qu'ran against this.
"The Arguments
Some of the reasoning used by voices against stunning is based around the following ayat of the Quran:
"Forbidden to you (for food) are dead animal, blood, the flesh of swine, and that over which has been invoked other than the name of Allah, that which has been killed by strangling or by a violent blow or by a headlong fall or by being gored to death, that which has been partly eaten by a wild animal, unless you are able to slaughter (in due form), and that which is sacrificed on stone (altars)." (5:3)
The authorities argue that:
1) Research has shown that animals can and do die from stunning. If an animal dies because of stunning it is haram to eat. As we can't be 100% sure that the animal was alive at the time of slaughter we should then avoid all stunned meat.
We are partly in agreement. However, as we work in an abattoir we know from first hand experience that it is impossible for a lamb to die from a low voltage stun. In addition, if we follow the logic that because an animal may "possibly die" before slaughter we should not eat it, then why do we not also apply that logic to the person slaughtering the animal? They "possibly" did not follow the correct procedures for the slaughtering in terms of carrying it out properly and as a result we should consider the meat as haram. In fact the chances of this happening are higher than an animal dying from stunning.
2) The ayah says, "forbidden to you is the blood to consume." The halal authorities state that blood is dangerous if left inside the meat. Stunning can cause more blood to stay in the animal if the animal dies before being slaughtered.
Again, this is only applicable to an animal that dies before slaughter. It is not applicable to those that are still alive with hearts pumping when slaughtered meaning the blood runs free from the animal just as it would if it were alive. Furthemore, there is independent research to suggest the bleeding of stunned animals is equal to those on un-stunned.
3) The ayah says, "and an animal killed by a violent blow". This is compared to the act of stunning an animal and therefore invalidates it being halal.
Anyone who works in an abattoir will tell you that when you stun a lamb, there is absolutely no "blow" as this would make it impossible to stun it. The tongs must be carefully placed on the head otherwise they would not stay there."
The key is therefore for the electric stun to be strong enough to render the animal unconscious for just long enough, but not to kill - and as such is totally acceptable according to the Qu'ran - and in my view the best compromise possible.