The kosher killing of clean animals sounds horrible. However, when done
right, the throat is cleanly slit and the animals heart pumps the blood out
of the body. The animal grow weak, kneels down, and falls asleep. It is the
blood that carries many of the impurities of the body.
If you go to visit Iseral, you'll see many market with kosher killed meat
hanging the carcases out in the open. The flies don't seem to be attacted
to them.