There is a handy diagram on the back label of your turducken that
illustrates this.  First remove / cut away the wings.  2nd, make a cut
straight down the middle of the turducken lengthwise (cutting the
turducken completely in half).  Take one half and turn over so the flat
edge that you just cut along is facing down. Cut into equal width
slices, and then repeat with the other half.  An electric knife works
well.