For anyone interested in cooking turducken, I roasted one for Christmas dinner. I bought it at the Gourmet Butcher Block in the New Orleans metropolitan area, one of the top local purveyors of this specialty. It was frozen when I purchased it, and I followed the accompanying instructions and thawed it for five days in the refrigerator, then roasted it for four hours covered at 375 degrees, plus one hour uncovered. It was dry. There were only four of us so we didn't get that far into the body during dinner, but we found out later when we were carving more slices to send home with our guests that we had never really made it to the duck, which was more to the middle of the thing.
My advice -- back off on the cooking time for about 45 minutes from the recommended time. Or use a meat thermometer, which I didn't think to do.