I've seen wet stones explode on a fire
but properly done beercan chicken can be worth digging shrapnel out of your eyelid.
( M3rx likes the Asian ladies, Fri 27 May 2011, 12:39, 2 replies)

This^ Beat me to it.
Dry stones ONLY!! Or your food will be everywhere but where you want it.

And an old biscuit tin with the chicken in, buried under the fire will work wonders;-)

Edit, hope you get the weather for it, we're off on Sunday for a weeks glamping too.
( Blind Meach Cautiously optimistic, Fri 27 May 2011, 13:14, closed)

I put the giant stones next to the fire rather than in the middle. That would be lunacy. Just pile the embers up at the side.

A couple of hours drinking round the fire then the chicken's done.
(Barry Subchimp, Fri 27 May 2011, 13:35, closed)