The order Anseriformes include ducks, geese, and swans. These waterfowl vary from strictly herbivorous (swans, most geese, most ducks) to highly piscivorous (marine ducks, mergansers). Commercial duck or game-bird pellets are available but not suitable for all species.
Swans are herbivorous, and pellets made specifically for these species should be provided. Diets of lettuce and corn, which are unfortunately often provided, lead to protein and multiple vitamin deficiencies. These often manifest as poor plumage, swollen joints, and pododermatitis.
As is true for most bird species, young waterfowl should be fed starter pellets with higher fat and protein content. However, excessively rapid growth of large waterfowl must be avoided to prevent bone and joint deformities, such as angel wing and perosis.
Last full review/revision July 2011 by Joeke Nijboer, PhD; Teresa L. Lightfoot, DVM, DABVP (Avian)