Hardware Disease & Metal Toxicity In Chickens

Zinc Toxicity

Chickens explore their world beak first and often peck at things that aren’t edible or healthy. If they manage to ingest metal objects they can lead to poisoning. Once inside the digestive system metal begins to corrode and zinc is absorbed into the bloodstream causing damage to, and rupture of, red blood cells.

So how are our birds finding zinc? If you use any metal that has a protective galvanized coating it contains zinc (i.e. off-cuts from metal hardware cloth, nails, screws, nuts and bolts). My birds are often unearthing some long-lost bits of refuse – broken glass, metallic toys, bottle caps – so I’d be curious to know if they’ve ever eaten any of it without my knowledge.

 Symptoms

• Staggering, loss of balance, difficulty walking, loss of coordination, falling, stumbling, unsteady, tumbling
• Diarrhea, stinky poop
• Pale skin around the face, comb and wattles
• Leg paralysis, walking stiffly, unable or inability to move, lower limb rigidity
• Production of large volumes of dilute urine
• Excessive drinking
• Decreased appetite
• Weakness, inability to stand, sitting/resting on hocks, limp/lame
• Weight loss

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Lead Poisoning

When I owned my first house I had all the lead sewage lines replaced with PVC pipes. Old houses are full of flaking lead paint and many other products contain lead: batteries, asphalt, leaded gasoline, lead shot, plastic toys and car oil. All of those heavy metals leach into our environment: water and soil.

Backyard chickens in cities are increasingly being exposed to lead poisoning from contaminated soil. Vegetation that grows on that soil will be a risk for foraging birds. If you use ceramic glazed bowls for your flock’s food or water they may also contain lead.

Lead is a neurotoxin which, when ingested, remains in the chicken’s digestive tract and is stored in the liver, kidneys and bones. It then gets absorbed into the bloodstream, causing anemia and reduces the bird’s ability to absorb calcium. If laying hens are affected the lead can be deposited in both the egg shell and yolk, which has ramifications for human consumption.

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Symptoms

Acute form:

• Sudden onset of muscle weakness
• Loss of appetite
• Weight loss
• Unsteady gait
• Drop in egg production
• Severe anemia
• Head tilt
• Walking in circles
• Blindness
• Seizures

Chronic form:

• Affects nerves, which results in decreased movement in the gastrointestinal system
• Delayed crop emptying, sour or impacted crop.
• Green diarrhea, stained vent feathers

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Diagnosis and Treatment

Most birds suffering metal toxicity will probably die or be euthanized without a known cause of death. I always encourage folks, if they are able, to send a bird that has died unexpectedly or of unknown causes for a necropsy.

For those who are willing, and able, to take an affected bird to a veterinarian they may be able to come up with a diagnosis through a blood test. If a bird has only ingested a contaminated plant or soil then the treatment is supportive care (isolation, food and water), chelation therapy (medications that bind to the metals, which are then excreted out of the body) and removing lead from the environment (easier said than done if it’s in the soil). Small metal particles can be flushed out of the digestive system by administering mineral oil, peanut butter or Epsom salts dissolved in water.

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The most effective diagnostic tool for finding ingested metal debris is x-rays of the gizzard and stomach. Of course, if foreign objects were found the recommendation would be to have them surgically removed. Many people, at that point, would opt to have their bird euthanized rather than spend a fair bit of money on an operation for a chicken.

I read of two cases recently in a Facebook chicken group: two birds had ingested pieces of metal that were surgically removed. Both birds made it through surgery, but sadly one died the next day. Fortunately, the other one, Bird Bird, has survived to tell the tale. Read her story is here.

Credits: Bird Vet Melbourne, Edgar’s Mission, Poultry DVM, Texas A&M. Feature photo: Business Insider