I'm not familiar with the phrase "half chicken statistics", and a basic google search was unhelpful. What does that generally refer to?
"If one person eats a chicken and another person doesn't eat anything, on average they both ate half a chicken"
Or in a similar way something like:
"If I eat two chickens and you eat none, statistically we both ate one"
Not sure where I heard that.
Also, the average human has less than two legs and less than two arms.
[0] http://www.fotografi.org/studi_settore/polli_di_trilussa.htm