Many people have many suggestions about how to kill a bird. Most suggestions are ways to make it easier on you but harder on the bird. One particularly horrible method is to put the bird in a closed container with a cloth soaked in lighter fluid. Another way people claim is humane is to put the bird in a freezer and freeze the bird to death. If this is just like going to sleep, why are we so very uncomfortable when we get just a little cold?
The way the Milwaukee County Zoo kills sick birds is the most humane and also the way suggested by Gail Damerow in her book The Chicken Health Handbook.
This method is a bit hard on you because you have to do it. It is very easy on the bird. It is quick and the last thing the bird knows is being gently held by someone she trusts. And it is this trust that you fulfill when killing a bird to put it out of misery.
The Chicken Health Handbook by Gail Damerow says:
"The best way to kill a chicken is to stretch its neck, which painlessly breaks the neck and spinal cord. With one hand, hold the bird's feet. Grasp the bird's head with the other hand, your thumb behind its comb and your little finger behind its beak. Tilt the head back and pull steadily until the head is separated from the neck."
The bird will struggle when the spinal cord snaps but it is already dead. Perhaps you want to give your friend a few treats like chopped hard boiled or microwaved egg, chopped greens, or scratch grains before she dies.
Please Read The Rainbow Bridge.