It's a tradition to "shlog caparah" which means killing a chicken instead of the ritual sacrifices that were made in the temple. Then the chickens would be given to institutions and used for food.
"Shechita" Jewish ritual slaughter is very humane. Basically the shochet takes an ultra sharp knife and severs the main artery so that the animal looses consciousness. Also, if the animal shows any awareness of death, like a lamb that runs away from the shochet, then you're not allowed to kill it.
There's a ban on "Shechita" in Switzerland because those great humanitarians, (the Swiss,who aided and abetted the Nazis and refused to return funds deposited by Jews during the War) think it's inhumane. It's actually a way to keep the Jewish community small because all kosher food (except chocolate for export) has to be imported.