Lead Poisoning in Birds: Signs, Diagnosis and Treatment

Free-ranging chickens can encounter plenty of hazards, but one that is easily overlooked is lead.

Lead exposure is particularly important in backyard poultry because it can affect the health of the bird and may also result in lead being deposited into eggs intended for human consumption.

Older properties, sheds, workshops and areas containing old building materials can all provide potential sources of exposure.

How Do Chickens Get Lead Poisoning?

Chickens naturally scratch, peck and investigate their environment. This makes them particularly good at finding small pieces of metal, old paint and other contaminated material.

Once swallowed, lead can remain within the gastrointestinal tract and gradually be absorbed into the bloodstream.

The severity of poisoning depends on both the amount of lead ingested and the duration of exposure.

Signs of Lead Poisoning in Chickens

Lead toxicity can present in several different ways, which can make it difficult to recognise from clinical signs alone.

Acute Lead Poisoning

Following significant exposure, signs may develop relatively quickly and can include:

• Loss of appetite
• Weight loss
• Weakness
• Ataxia or difficulty walking
• Neurological abnormalities
• Anaemia
• Severe lethargy

Chronic Lead Exposure

Lower-level exposure over a longer period can produce much less obvious signs.

These may include:

• Progressive weight loss
• Reduced appetite
• Weakness or poor coordination
• Reduced gastrointestinal motility
• Crop stasis
• Abnormal or greenish droppings
• Vent soiling
• Reduced activity
• Poor general condition

Unfortunately, many of these signs can occur with other diseases, so lead poisoning cannot be reliably diagnosed from symptoms alone.

Diagnosing Lead Poisoning

A blood lead test is one of the most useful ways to investigate suspected lead exposure.

Radiographs can also be valuable, particularly when pieces of metal or other radiopaque material remain within the gastrointestinal tract.

However, a normal radiograph does not rule out lead poisoning. A bird may have absorbed lead without any visible material remaining in the digestive system.

Additional blood testing may identify abnormalities such as anaemia and can help assess the bird's overall condition.

Treating Lead Poisoning

Treatment depends on the severity of poisoning, whether lead remains within the gastrointestinal tract and the condition of the bird.

Supportive Care

Sick birds may require:

• Warmth
• Fluid therapy
• Nutritional support
• Assisted feeding where appropriate
• Management of gastrointestinal dysfunction
• Treatment of secondary complications

Supportive care can be extremely important while the source of lead is identified and removed.

Removing Lead From the Gastrointestinal Tract

If lead-containing material remains within the digestive tract, removing it can reduce continued absorption.

The appropriate approach depends on the location, size and type of material present. Veterinary treatment may involve gastrointestinal flushing or other techniques to encourage removal, and occasionally more direct intervention may be required.

This is preferable to relying on home remedies such as activated charcoal, which is not considered an effective treatment for lead poisoning.

Chelation Therapy

Chelating agents bind to absorbed lead so that it can be eliminated from the body.

Veterinary treatment may involve medications such as:

• Calcium disodium EDTA
• Succimer (DMSA)
• D-penicillamine

The choice of medication and treatment protocol depends on the individual case and should be managed by a veterinarian.

What About the Eggs?

This is an important consideration with backyard chickens.

Lead exposure in laying hens can result in lead contamination of their eggs, creating a potential human food-safety issue.

If lead exposure is suspected or confirmed, eggs from affected birds should not simply be assumed to be safe to eat.

The environmental source also needs to be identified and removed before the flock can be considered protected from further exposure.

Common Sources of Lead Around Chickens

The best treatment for lead poisoning is preventing exposure in the first place.

When inspecting a chicken's environment, try looking at it from their perspective. Chickens will investigate objects and areas that we might otherwise completely overlook.

Potential sources include:

• Old or flaking lead-based paint
• Lead shot and pellets
• Fishing sinkers and weights
• Lead solder
• Contaminated soil around older buildings
• Old building and roofing materials
• Some metal objects and hardware
• Stained-glass materials
• Jewellery and decorative objects
• Renovation and demolition debris
• Areas previously used for shooting or industrial activities

The Takeaway

Lead poisoning should be considered when a backyard chicken develops unexplained neurological signs, weakness, gastrointestinal problems, weight loss or anaemia, particularly when there is a plausible environmental source.

Diagnosis usually involves blood testing, with radiographs and additional laboratory testing providing further information.

Most importantly, lead poisoning is an environmental problem as well as a medical one. Treating an affected chicken without identifying and removing the source leaves the bird, the rest of the flock and potentially the people eating their eggs at continued risk.

Written by Dr Sam Hurley, BSc, BVSc, MAHM