I’ve never heard this term before, and within 24 hrs, it’s popped up about 6 times now! What the hay?
There’s bliss in being part of the uninformed… 
- Jinx
To be slightly disparaging, it’s basically interior decorating for new age crystal clutchers. More accurately, it’s a way of balancing the energy in your living space, everything from the site and alignment of the building to the placement and color of decor.
Be glad it took to long. I’ve been seeing way too much of this crap for years.
Now, to answer your question.
The hay is something you feed to cows and other livestock. If you are Cary Grant or Claudette Colbert you can eat stolen carrots while sitting on a big pile of it.
Alternatively, it is a Canadian river.
Feng Shui is a Chinese folk practice where one balances the energy of one’s home to make it a nice place to live. To me it looks like interior decorating with the paranormal. 
For the most part, homes designed with Feng Shui in mind look pretty nice but I have seen nothing completely spectacular.
HUGS!
Sqrl
For more detail than you really wanted, look at the last post in this thread.
Ah, crud. It’s gotten more posts since I bookmarked it. Look at the posts by hedra.
Anybody ever read the Vertigo comics series “The Enigma”?
–Cliffy