Answer:
   
   Slaughtering an animal is a complicated process. One must use an
   extremely sharp knife, and in a single action must slice through both
   the windpipe and the artery carrying blood to the head. This
   immediately renders the animal unconscious -- it dies before having
   the opportunity to feel any pain. The knife itself must be sharpened
   to perfection -- to the point that one cannot feel any imperfections
   in the blade. Otherwise the animal is rendered non-kosher. In
   addition, a detailed examination of the animal must be performed
   afterwards, to ensure that it was not sick or disabled. There is a
   blessing said in advance, as there is before performing any
   commandment, but this is not a prerequisite (and in addition, one
   blessing said in the morning applies to all animals a professional
   ritual slaughterer does that day). The word "professional" is very
   appropriate--it takes months of training for someone who is already a
   Rabbi to learn how to do this properly. The result, though, is the
   kosher animals are healthy and died with minimum pain.