...Is this a common problem in Norway?!
How do you distinguish between "You must not kiss the cow" and "You do not have to kiss the cow"?
You can use "Du er ikke nødt til å..." for the latter if you want to remove all doubt, but usually context and intonation does the job for you.
Maybe the second one could be 'Du trenger ikke å kysse kua'?
Have you seen the size of their tongues?
But what about the chicken?
You'll have to ask him... if you can find him, that is. ;)
Oh, there has GOT to be a good story behind this sentence!