This little project has me intrigued, so I am doing some more googling.

This one pretty much takes pig cooking in the ground out of the reach of your average unprepared wannabe pig cooker, without a lot of equipment.

This one tells how to do it like they do in Hawaii (you bring the rum).

And this one actually talks about cooking birds in clay mud, feathers and all. But it does not give a whole lot of info. Guess some willing birds are required for some experimenting...