Beware! It's raining Chicken from the Sky!

Raining Chicken all the way across the Sky! What does it mean?

A teen's horseback riding lesson ended abruptly after a foot-long hunk of raw chicken that fell out of a cloudless sky hit her in the head. […] Bernard, who was not injured, was wearing a riding helmet when the chicken hit her. Protecting a rider from unidentified flying chicken parts is not the helmet's normal function, but it did the trick.

It's raining chicken