Zinc toxicosis occurs somewhat often in domestic and wild waterfowl, such as ducks. In wild ducks, it is usually caused by an environmental spill or purposeful dumping of heavy metal into natural water bodies such as lakes, streams, rivers, detention ponds, etc. In domestic ducks, it is most often the result of ducks eating small and shiny metal objects containing zinc. Ducks will find zinc objects while dabbling in mud in backyards, within their pens, or inside homes or barns where ducks are brought into and left to roam.
When ducks ingest a zinc object, such as a penny, as the gastrointestinal track begins to break down the object, the zinc coating is released and absorbed within the body. Once absorbed, zinc will cause damage to the duck's red blood cells, pancreas and gizzard. Zinc toxicosis can present as an acute or chronic form, depending on the amount of zinc ingested and/or how quickly the object containing the zinc is absorbed into the duck's bloodstream. Zinc toxicosis often resembles lead intoxication.
Zinc and zinc compounds are used in galvanizing steel or iron, production of brass, bronze, and other alloy metals. This is important to keep in mind, being that almost any steel product that is sold and marketed as 'for outdoor use', more than likely has been galvanized. Sources of zinc include:
- United States (US) pennies made after 1983: In most cases, swallowing a single US penny (one cent coin) can be fatal to ducks; post-1983 pennies contain 98% (2,440 mg) of zinc.
- Connecting hardware: Nails, bolts, plumbing nuts, nuts, washers, screws, staples, etc.
- Galvanized metal: Hardware cloth, chain link fence materials, coated metal cage wire, metal bowls
- Improperly mixed waterfowl or poultry feeds
- Human body care products: Anti-dandruff shampoos, deodorant, diaper rash ointment contain zinc
- Other tiny metal objects: Zippers, keys, Monopoly game pieces, bird toy snaps, cage clips
- Antifouling paints
- Environment: Contaminated soil, vegetation, or water.