Supraorbital salt-excreting glands are present in at least 10 avian orders and are largest in marine species, including penguins. Diseases of the avian salt gland have been described infrequently. From September 2015, five captive northern rockhopper penguins (Eudyptes moseleyi) were presented over a 6-wk period for unilateral or bilateral supraorbital swellings. In September 2016, two cases recurred and two additional cases were identified. Histopathology demonstrated salt gland adenitis with extensive squamous metaplasia. Blood plasma testing demonstrated marked vitamin A and E deficiencies within the colony. Prolonged frozen storage of feed-fish was implicated as a cause of vitamin depletion; reducing storage times and addition of dietary supplementation prevented recurrence.