I've done a turducken twice -- a large turkey, with a duck, chicken, and cornish game hen inside. But for good measure, I sewed that up, and put it inside a 50 lb. pig (after taking out its ribs and backbone.
And I actually smoked it for around 13 hours at around 250-275 degrees. The internal temps for all got up over the levels required for poultry (and each time I smoked them it served around 50 people and no one got sick). They were delicious and not simply a novelty.
I'm smoking 2 turducken creations this thanksgiving. This time they'll have different marinades and stuffings, and I'm going to intersperse one with lamb, and the other with bacon and corned beef (which requires some cooking to tenderize it before putting it in).
I lost the pictures of the piggerduckenhens I did last year, but will post these since I just found this forum.
My only beef with a turducken is the duck . . . I don't love it because it gets dry. Maybe wrapping it in bacon thoroughly may help this year.
And this is my first time smoking a turducken without the protective coating of a pig, so that may cause some difficulties. I'm thinking of wrapping it in aluminum foil after a few hours so the tender outside skin doesn't get charred.
Just thought I'd share. With a 25 lb turkey available for $14, and the other fowl cheap as well, it really is worth experimenting with.