Like a Chicken with Its Head Cut Off

I'm glad to say I've never seen an example of the cliche's source.

I do, however, remember watching my mother try to kill a chicken. She was torturing the poor thing, doing a terrible job, flinging it round and back, whimpering.

Fortunately, our housekeeper Lucille heard Mother's gasps, came out, took that chicken, gave it one strong snap, and broke its neck. It did not move again.

I can't say the same of what's left of this little Eastern Amberwing.

This poor fellow had been half eaten when I found him on a stone a water's edge, still grappling with his legs, his head twisting, his abdomen missing. How that's possible, I don't know. 

I do know that in my hand he flopped from side to side, in a hideous little death dance, and I remembered that day in childhood.