Re this article
First of all, you’re reading an article translated from Norwegian into English. Whatever the original Swedish term was, it was not “chicken shock”.
Secondly, it’s quite obvious that the phrase was referring to the fact that the princess looks like a freakin’ chicken right out of some hideous children’s Easter party. Some people wear shock pink; some wear shock chicken.
Yes, gentle, as a matter of fact the original Swedish is, literally translated, “chicken shock” - kycklingchock. The article in question was found via Google on the website for Sweden’s Aftonbladet for the day of 23 May. Scroll down until you see the picture of Märtha Louise in the dress and you can’t miss it.
What does it mean? Like as not it was a neologism coined by the folks at Aftonbladet (roughly the Swedish equivalent of the New York Post) to try and describe the dress, which is rather shocking and indeed makes her look like she’s wearing a chicken costume. But when you consider it got one sentence in an article at the main conservative paper (Svenska Dagbladet) and didn’t even register at all with the main left-leaning paper (Dagens Nyheter), you get the idea that the dress wasn’t all that big of a deal in the first place and that Aftonbladet was just looking for something to talk about.
The word in question seems to originate from an article in the Swedish newspaper Aftonbladet, by Kerstin Danielson and Lotta Zachrisson.
The exact word used was “kycklingchock” which does not mean much of anything, and which does not appear to occur on any web pages other than that article and other pages on aftonbladet.se mentioning it.
Quite probably, whichever of the two authors that is responsible for the word is a bad speller, and was going for “kycklingschock”, which does indeed mean “chicken schock”. The word “kycklingschock” does not occur on any web pages indexed by Google; it seems to be an invention of the ladies in question.
What they were trying to convey by it, other than the fact that the princess’s outfit did indeed bring poultry to mind, is anyone’s guess.
(On preview, I see Olentzero preempted me. But I typed this stuff, and even proofread it, I’m damn well going to post it.)
(Except I’m a moron - chock is indeed the correct Swedish spelling. Clearly, I’ve been neglecting my mother’s tongue lately. Do ignore me.)
Fan nej, det är ju bra att se andra som talar svenska här! 
Perhaps they meant to say “chicken shark”, in which case the context becomes clear to all but the most ignorant among us.
I just felt a bit bad about insulting someone for their spelling, when it was in fact correct :).
Which was precisely my point – chicken shock is not Swedish; kycklingchock is. I was merely pointing out that the question was badly worded.