[1] Working at the National Health Laboratories (now ESR), Hayden was responsible for assessing public safety of cultured shellfish, which led to her taking a job at the Fisheries Research Division of MAF.
[1] Hayden completed a PhD titled Factors affecting recruitment of farmed greenshell mussels, Perna canaliculus (Gmelin) 1791, in Marlborough Sounds at the University of Otago.
[4] She was a founding member of the New Zealand Sanitation Committee, which drew up quality assurance guidelines for exported shellfish.
[4] Hayden was appointed Chief Scientist of NIWA's National Centre for Aquatic Biodiversity and Biosecurity in 2010, taking over from Don Robertson.
[4][5] She is a member of the International Union for Conservation of Nature Invasive Species Specialist Group.