Because of the obvious mistreatment of animals in slaughter houses the thought has come up that it might be better just to make the animals feel less pain as a way of make the process more human. The idea would be to genetically modify the animal so that it would no longer be able to feel pain, this way chickens would not have to go through the torcher of having there beaks cut off with out antithetic, and cows and pigs would have some relief from the pain of every day life.
To me this is not the way to fix a problem, if you always just smooth over a problem rather than trying to find the origin of the issue and resolving from the beginning. We need to make the living conditions better before we try and change the vary structure of an animal.