This in no way means that all non kosher slaughter methods are bad. Rather, the biggest problem with modern-day killing of poultry, is, as mentioned before, the highly unreliable water bath stunning system. The first good alternative that people usually discuss (mentioned in the above PETA video), is controlled atmospheric killing (CAK). This method uses gas to put the birds to sleep and according to many top animal welfare researchers, including kosher champion Temple Grandin, is quite effective and humane.* The main problem with this type of slaughter, however, is that it only works on hybridized chickens and turkeys. Because heritage birds and other species such as ducks and geese all have much stronger lungs and organs, they react violently to the gas.
Another promising new technology is the TopKip VOLTA. This system, featured in the video above, supplies the precise level of voltage required to stun each chicken, by continuously measuring the amount of electricity needed to do so for each individual bird. It has won several humane poultry awards and seems to be another promising alternative for fast-paced automatic slaughter. Although I don't think it would be effective for non-industrialized birds either, as they tend vary in size much more than generic ‘supermarket’ poultry.
There are some seemingly effective means of non-mechanized non-kosher poultry slaughter that are in small scale use today. These methods can effectively promote a more humane and personal approach to ending an animal’s life. The most widespread of these is the stunning knife. When used each animal is stunned by hand by way of an electric knife and then bled out by way of a cut made with that same instrument. If administered correctly this system seems reliable and can work well on a healthy and diverse range of poultry. Like any other method it also has its downsides but overall it seems to be a balanced and effective approach.