American College of Poultry Veterinarians (ACPV)
- Small Animal Orthopedic Surgeon – UNAM, Mexico 1984-1985
- Broiler production - Corporate Veterinarian (CAM, Morelos, Mexico) 1985
- Salsbury Laboratories, Mexico – Director of Veterinary Services 1985-1988
- Avian Farms International, Inc. USA – Director of Veterinary Services 1992-1998
- Merial Laboratories USA – Director of Veterinary Services 1998
- University of Melbourne, Melbourne, Australia – Research Fellow 2000-2001
- Georgia Poultry Laboratory Network – Pathologist and Virologist 2001-2003
- University of Georgia – Assistant Professor, Associate Professor, Professor – Clinical Avian Medicine, Virology Researcher, Instructor 2003-2014
- Avian Health International, LLC – Poultry Consultant - Owner and Founder 2014-2015
Avian Health International, LLC is a poultry consulting firm. As a founder and owner, Dr. Zavala provides veterinary and husbandry advice in multiple countries of the Americas, Europe, Australia and Asia.
32 publications in peer reviewed (refereed) journals.
Author or coauthor of book chapters in avian retroviruses in reference 3 books.
Over 175 conferences in 5 continents since 2001.