[Rupert the bear]

We use a bolt gun to the back of the head.
We adapted a square wooden 'stepping stone' with a channel to lay the goose's neck in with a toggle to keep the head still. Hubby lays the bird so that the neck is in the channel; I turn the toggle to hold the head firm and the use the bolt gun to the back of the head. Instantaneous', humane, and quick. It is then transported to the house upside down to bleed out (which is does freely).
We have tried every which way to do the deed humanely and have hated most of them; I don't raise my birds/animals to cause them stress at the end..............
We bought our bolt gun from Belgium, if anyone is interested.

This is the method we use , and I feel is the best.