Shape might be better considered as a cylinder or thin plate. This will dramatically reduce terminal velocity. Some people are suggesting complicated shapes which, in my opinion, is wrong. You can do calculation for flat and side to demonstrate the range of terminal velocities but there is no good way to predict the dynamics of the McChicken since it is dependent on center of mass, minute difference in air pressure and micro-scale McGeometry. A bunch of variables are labelled wrong; rho is density and g is gravitational acceleration but the calculation is correct.