is an arabic word means Divinely allowed, halal meat is the meat of an animal or a bird that was slaughtered according to Islamic teachings. Islamic slaughter involves many things to ensure humane treatment of the animal. First, feeding the animal and giving it water & shade during the days of preparation, out of mercy, so that it does not hunger or thirst. Then, separating it from all the other animals during the slaughter, so that they don't see each other. Then directing it to face the Kaaba in Macca, hiding the knife all the time from it, while saying "In the name of Allah, Allah is the greatest" and slaughtering it rapidly with a very sharp knife. The cut must sever the Carotid arteries, the Jugular veins, and also the oesophagus and the trachea, and stop only at the vertebral column in a single, rapid & very deep act. This method ensures many things, first, that the animals do not see any act of slaughter to other animals, and the animal to be slaughtered itself is not aware it is being prepared for slaughter, so it is not frightened and stays calm. Once the knife touches and cuts the carotids, it loses consciousness, and that's why the knife has to be sharp, to reach and cut the carotids rapidly. The spinal cord is not cut, so it keeps discharging automatic impulses to the body muscles to contract even after the animal loses all awareness, this pumps all the animal's blood outside its body through the great vessels, which is hygienic as it leaves the meat bloodless.
The claim that the animal suffers is debatable because of two physiological mechanisms; Vasovagal syncope occurs if the carotid sheath is traumatized which is enough to cause immediate blackout, and Brain Ischemia which occurs when blood ceases to flow to the brain, also causing the creature to pass out almost instantaneously, and when this ischemia continues, brain death ensues, without a functioning "Sensory system" to perceive this alleged pain.
So in the end, the animal passes out and dies in peace leaving hygienic meat.