Chris the Rhea is on the loose and spooking horses, "The runaway rhea which can disembowel a man with its mighty legs and six inch claws is reported to be worrying horses."

http://www.hertfordshiremercury.co.uk/Buntingford-and-Royston/Horse-riders-in-Hertfordshire-warned-as-escaped-rhea-spooks-horse-20140417132434.htm

There's even a video on the Telegraph website: http://www.telegraph.co.uk/news/newstopics/howaboutthat/10772907/Hertfordshire-Rhea-hunt-First-video-of-bird-that-can-disembowel.html