I've seen pictures of the Maasai in Africa when they collect blood from cows for drinking. The cows are barely restrained. I have no doubt that such blood letting could be done to death without causing undue stress to the animal. The trick would be a very very sharp knife or an arrow (as the Maasai use). I think very few people now days are capable of sharpening a knife to the required sharpness and you would have to be very accurate. I think a large animal would be much easier than a small one in most cases.
I have never tried this, so just my thoughts on the matter.
I have never tried this, so just my thoughts on the matter.