I don't think you can call that halal cos the name of the lord has to be pronounced on the Animal in a clear manner before you cut the jugular, which gets rid of the toxic blood, and the belief that the animal is honoured to be slaughtered in the name of it's creator.you can hear it choking on it's own blood..
they also break the halal rules because the other sheep shouldn't have seen it.. it causes them stress to see their friends killed.. apparently
I've seen another video ( which I can't link to because the site also contains some really dubious stuff and pron.. ), where they slaughter a goat..
it's standing nice and quiet and calm, then a bloke walks up to it and takes it's head clean off ( one chop, execution style ) with a large knife similar in size to a machette..
it doesn't see it coming and is dead before it knows it..
there's nothing in the halal rules that say they can't gas the animals into unconciousness, as long as it would recover if not killed afterwards..
But you might disagree.
I prefer lamb to sheep or Cow but don't mind cos it all tastes good when you're hungry.