I've been thinking about the following quote from Churchill
"The contribution of Canada to the Imperial war effort in troops, in ships, in aircraft, in food, and in finance has been magnificent.....Hitler and his Nazi gang have sown the wind: let them reap the whirlwind.......When I warned them (the French) that Britain would fight on alone whatever they did their generals told their Prime Minister and his divided Cabinet, 'In three weeks England would have her neck wrung like a chicken.' Some chicken! Some Neck." Canadian Parliament 30 December 1941
When he says "Some chicken", PMs start laughing, and when he says "Some Neck" they laugh again. I'm not a native English speaker. I miss the the joke of this.
What does "some chicken, some neck" mean in this context and why is it funny?
The video can be found here