I'd heard of the 17-bird roast before through TV Tropes (http://tvtropes.org/pmwiki/pmwiki.php/IAmNotMakingThisUp/Animals), though that doesn't make it any less crazy.

. . . at least it was a feast? They could have had hundreds of people to feed, which makes it slightly more reasonable. Plus, the royals probably wanted to impress people with their craziness and money. :p