The Rotating Chicken question

Recently, Anny Matar and others wrote about the Rotating Chicken on the Cz-L list.

Here’s a snippit of what Anny wrote:  […]I dreaded Yom Kippur becausemy Zazia, as we called grandfather, turned the chickens over our heads andwe had to say:”Mir zum Leben dir zum Tod” (me to life and you to death) and that was a terrible thing, never to be forgotten. Then the Shohat came, by then I was as far and as fast as my feet could carry me when I only saw that man……)!!!

Now my question is: from what did this originate; and what is the meaning; and why a chicken? Enquiring minds want to know!

Best,

jerome