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Zinc Toxicity

New Wire Disease

Zinc toxicity is a serious condition caused by ingestion of excessive amounts of zinc (Zn). Zinc is an important chemical element, mineral, and metal, that is required to maintain proper health function in chickens. However, ingestion of high amounts of zinc is harmful, and potentially fatal to chickens. Zinc and zinc compounds are used in numerous commercial applications (galvanizing steel or iron, production of brass, bronze, and other alloy metals) and various, frequently used and common products. Common sources of zinc for backyard chickens include:
  • Improperly mixed chicken feeds
  • Soil
  • Hardware cloth
  • Chain link fencing
  • Powder coated metal cages used for small animals
  • Metal water or feed bowels
  • Temporary housing cage clips or staples
  • Snap fasteners, padlocks, and some toy snaps or hangers
  • United States pennies made after 1983 (one penny contains ~ 2440 mg of zinc)
  • Keys
  • Nails, washers, nuts and bolts
  • Zinc oxide cream or ointment (such as Desitin or generic diaper rash ointment)
  • Deodorant
  • Anti-dandruff shampoos
  • Antifouling paints
  • Fertilizers
  • Zippers
  • Monopoly game pieces
Chickens that are allowed to free range may potentially pick up and ingest buried metal, coins, galvanized nails and other zinc produced products.

Clinical Signs of Zinc Poisoning

Chickens can display a wide range of clinical signs, which may include:
  • Lethargy
  • Pale comb
  • Regurgitation
  • Cyanosis (bluing of comb)
  • Weight loss
  • Shallow respiration
  • Reduced appetite
  • Weakness
  • Polyuria (production of abnormally large volumes of dilute urine)
  • Polydipsia (excessive or excess drinking)
  • Diarrhea
  • Melena (dark sticky feces containing partly digested blood)
  • Shivering
  • Feather picking
  • Death

Clinical Signs

Diarrhea, green or yellow in color
Increased thirst
Delayed crop emptying
Weight loss
Feather loss


  • History of exposure
  • Clinical signs
  • CBC - mild to moderate anemia
  • Blood test - plasma zinc concentrations greater than 2 ppm
  • Post-mortem - levels greater than 1000 u/g in pancreatic tissue


Chelation therapy with edetate calcium disodium (CaEDTA)At 35 mg/kg IM q12 x 5 days, then 5 days off, then repeat if needed.
2, 3 dimercaptosuccinic acid (DMSA)30 mg/kg PO q24h x 5 days
D-PenicillamineAt 55 mg/kg PO q12h x 5 days and repeat after 5 days if needed. Easy to mix and be tube-fed to reduce treatment cost (125 mg capsule in 15 ml lactulose1 drop/100 g PO).
Supportive care
Concurrent parenteral fluid therapyVery important to prevent dehydration and to aid in getting rid of the toxic metals from the bird's systemS Gelis


  • Scrub any new galvanized webwire or cage wiring with a mildly acidic solution such as vinegar, then let dry in the sun (may help reduce the amount of zinc present)
  • Do not provide chickens access to objects containing high levels of zinc
  • Thoroughly scrub any newly purchased metal items that have been galvanized, (such as galvanized hardware cloth) and will be in contact with birds, with a mildly acidic solution such as vinegar, then carefully let dry.

Scientific References

Risk Factors

  • Letting chickens free range
  • Chickens kept inside as house pets