Mackenzie's research is on the functional morphology and evolution of bird postcrania.  After completing an undergraduate honor's thesis on the form and function of the tarsometatarsus in the giant Eocene bird Gastornis, she completed a Masters degree at Hays State University on the postcranial variation in Mesozoic sea birds, including Icthyornis.  She is now a PhD student at University of California, Berkeley.