Q:

How do I get to the "Fowl Lair"

In a separate forum I was reading, a poster described an easter egg area called "The Fowl Lair".  I could imagine that this is the replacement for the Cow Level from Diablo II, but I hope that is not the case.  How do I get to this area?  Are there any monsters or treasure to be had, or any other benefit to going there?

A:

To get to the Fowl Lair you need to use the Ancient Device in Desolate Sands. It is one of the 10 possible outcomes of using the Ancient Device. So take note that not only is the spawn of the device random but there's only 10% of getting the Fowl Lair.
Where are all the random dungeons?
This contains a community wiki of random locations and which zones they are in. It was revised to add Fowl Lair based on this forum thread:
http://us.battle.net/d3/en/forum/topic/5149619068 

The plateau on the map (obviously random location, but that's the shape)  

The Ancient Device

The entrance to the Fowl Lair after succesfully spawning it using the device (took A LOT of tries)  

Inside the Fowl Lair

