This just in: the Cockatrice is an actual creature that actually existed now.

Recently discovered dinosaur of the jurassic era “yi qi” may have flown on bat like wings

http://palaeoblog.blogspot.co.uk/2015/04/yi-qi-chinese-gliding-dinosaur.html?m=1

http://www.theguardian.com/science/lost-worlds/2015/apr/29/bird-yi-qi-the-dinosaur-evolution-flight-feather-nature