It was posted there, probably, after it appeared in the Fortean Times. The Fortean Times (for those who haven't had their weirdo coming-out yet) is a magazine dedicated to to the publication of news of weird events, often with questionable accuracy; it is named after Charles Fort, a guy who spend a lot of time scanning 20ies and 30ies newspapers ``researching'' fringe science. If you're looking for more weird or pathetic images, you might want to look at the Fortean Times photo highlights.
I found out about the Fortean source as I was on the brink of producing the world's first chicken death home page; but I won't do it with material that's so well-known among weirdoes. If you consider linking to the chicken image, or have linked to it, please link to the one at the Fortean Times, <a href="http://alpha.mic.dundee.ac.uk/ft/ft3.gif">.