Galvanized metal, which is coated with a protective zinc layer to prevent rusting, is commonly used for bird cages, aviaries, chicken coops, and other animal enclosures. However, there has been some debate over whether the zinc coating poses health risks to birds.
What is galvanized metal?
Galvanized metal refers to steel or iron that has been coated with zinc to protect it from corrosion. The zinc provides a protective barrier, preventing moisture from reaching the metal underneath. This galvanization process helps metal last longer, especially when exposed to the elements.
There are a few ways to galvanize metal:
- Hot-dip galvanizing submerges the metal in a bath of molten zinc to coat all surfaces.
- Electrogalvanizing applies the zinc coating through an electrical process.
- Mechanical galvanizing presses or rubs zinc powder onto the surface.
The thickness of the zinc coating depends on the method used. Hot-dip galvanizing typically produces the thickest and most durable coating.
Is galvanized metal toxic to birds?
The main concern with galvanized metal is the zinc coating. When exposed to water or moisture, the zinc can corrode or oxidize, forming sharp zinc spikes. These spikes can flake off and be ingested by birds.
Zinc is an essential mineral for birds, but ingesting excess amounts can be toxic. The oxidized zinc flakes have higher zinc concentrations than the underlying coating. Eating these concentrated zinc flakes is what poses a risk.
However, research shows minimal leaching of the zinc coating under typical use conditions. New galvanized metal generally does not present a toxicity risk.
The main factors that affect leaching and oxidization of the zinc layer are:
- Age: Older galvanized metal is more likely to have corrosion and flaking.
- Wear: Scratches and abrasions in the coating expose more metal.
- Exposure: Wet, outdoor, salty, or acidic environments corrode the zinc faster.
Signs of zinc toxicity
If a bird ingests excess zinc, it can cause toxicity signs including:
- Loss of appetite
- Digestive upset
- Vomiting
- Diarrhea
- Lethargy
- Weight loss
In severe cases, it can lead to anemia, pancreatitis, kidney or liver damage, or even death. Zinc toxicity can develop from a one-time large ingestion or chronic lower level exposure.
Safety tips for galvanized metal
To minimize risks when using galvanized metal around birds:
- Purchase new galvanized products to limit corrosion and flaking zinc.
- Avoid old, damaged galvanized metal with visible rusting or wear.
- Use a protective coating or barrier over any scratched sections.
- Choose electrogalvanized or mechanically galvanized metals which have thinner zinc layers.
- Prefer powder-coated metals as an alternative.
- Avoid contact with acidic liquids like juices that could react with the zinc.
- Clean any accumulated zinc corrosion buildup.
- Provide ample wash basins and water sources to minimize exposing metal to moisture.
- Regularly examine metal for any cracking or wearing off of the zinc coating.
- Remove and replace any galvanized metal at the first signs of oxidation.
Is galvanized metal completely unsafe for birds?
No, galvanized metal does not need to be completely avoided when housing or keeping birds. The risk of zinc toxicity mainly depends on the condition of the metal. New, high quality galvanized products are generally safe when used properly.
To put the amount of zinc in perspective, a study tested four hot-dipped galvanized steel animal feeders. Researchers estimated the actual amount of zinc ingested based on the zinc concentrations in the feeders was not likely to meet or exceed the daily requirements for poultry (National Research Council 1994).
Another study examined brand new galvanized drinkers, which birds can directly drink from. The total zinc exposure was calculated to still be within a safe range for poultry health (Burrell and Exner 1988).
The greatest risks come from aged, damaged galvanized metal that has exposed metal and built up zinc corrosion. This old metal has the potential for flaking off much higher zinc concentrations.
Other metals used for bird supplies
While galvanized steel comes with some concerns, there are other metal options for bird cages, feeders, and accessories that avoid zinc exposure:
- Stainless steel – Made of chromium and nickel for corrosion resistance without a zinc coating. More expensive but very durable.
- Powder coated metals – Has a plastic resin coating instead of zinc galvanization.
- Nickel plated – Provides a nickel coating without zinc.
- Copper – Naturally corrosion resistant. Can be pricey.
- Aluminum – Lightweight and often anodized for protection.
- Titanium – Extremely strong, lightweight, and nontoxic.
- Ceramic – Inert, non-porous, and waterproof.
Many bird owners prefer stainless steel cages, feeders, and bowls. Stainless steel provides durability without the risk of zinc exposure. Powder coated metals are another excellent choice.
Conclusion
Galvanized metal can potentially pose health risks to birds from zinc poisoning. However, brand new, high quality galvanized metal is generally considered safe when used properly for housing birds or poultry.
Avoid old, damaged galvanized metal items that are flaking or corroded. Also prevent exposing galvanized metal to moisture, acids, or abrasion that could wear off the zinc coating faster. Provide separate food and water containers.
With responsible precautions and monitoring for deterioration, galvanized metal can be an affordable option over more expensive stainless steel. Powder coated and ceramic supplies are also great alternatives. Being aware of the risks allows bird owners to safely use galvanized metal.
