Lead and Zinc– Hidden Dangers to Your Chickens

By Leigh -

When we hear about cases of lead poisoning, most of us think about children living in older homes with peeling paint or adults that work in industries where contaminated areas… we don’t tend to think about chickens. Unfortunately our backyard flocks may be at higher risk for lead poisoning than our children these days.  Worse yet, that lead can be passed to you (or to chicks) through your chicken’s eggs.

While most people living in older homes where lead paint may have been used (before 1978) have taken precautions, it can be easy to overlook chipping paint in an old shed or coop on the property. And those delicious-looking paint chips aren’t the only threat to our feathered flock of foragers. 

Many of us who keep chickens and try to live on the more organic side of life may also be avid hunters or anglers. Lead shot and fishing sinkers can pose a problem if they end up within reach of your curious and hungry birds.

Tire weights, lead pipes in your barnyard or coop plumbing, garden hoses, batteries, twist ties, products manufactured in certain parts of Asia and many household goods predating the 1970’s may also contain lead as well as many ceramic items. The soil itself can also be contaminated by past gasoline spills or landfill watershed.

In fact, the New York Times did an articlein October of this last year warning readers of findings of detectable lead contamination in the eggs of more than half of backyard chickens living in older neighborhoods in the Bronx, Queens and Brooklyn, NY. Some of the eggs tested averaged 11.5 micrograms of lead – almost twice the level the FDA deemed “acceptable” in 1993 for daily consumption by children under the age of 7.

So if you know there is a risk in the area your chickens are kept, what signs would you look for in your flock?

Well… with lower levels of lead contamination (say, from consuming a tiny paint chip or two) your chickens may not show any signs at all. This does not mean lead could not be present in the eggs. 

Fertile eggs from poultry contaminated with non-fatal levels of lead may die before or shortly after hatching, or produce live chicks with anomalies or deformities.

Poultry with higher contamination levels may exhibit the following symptoms:

Lethargy

Depression

Failure to grow or to maintain weight

Loose stools – greenish-black in color

Lack of balance

Disorientation

Inability to perch

Vomiting

Brain function disturbance

Loss of coordination

Loss of vision

Seizures

Inability to hold head straight

Death

Zinc, an even more prevalent substance these days, can also pose a poisoning threat to chickens. Zinc is present in galvanized feeders and in cage wire. While my personal choice would be to not use a galvanized pan or feeder for foodstuffs (and especially not for Fermented Feed), it is still generally safe to use galvanized wire… provided you do not leave any small clipped-off bits about where birds might ingest them.

Other coop-building and construction items like nails, washers and nuts may be produced with high zinc content, and US pennies minted after 1983 are 95.7 percent zinc. By nature, birds including chickens are attracted to shiny items, and because chickens spend much of their day searching the ground for interesting things to eat, small washers and wire bits may become a quick meal.

Signs of zinc poisoning in chickens include:

Loss of appetite / weight loss

Feather picking

Shallow breathing

Depression and lethargy

Weakness and shaking

Loss of balance

Diarrhea (in advanced cases stool may appear black and tarry)

Vomiting

Kidney, liver and pancreatic anomalies

Anemia

Death

Your best defense against heavy metal poisoning in your flock is to avoid playing too much AC/DC, Metallica or Black Sabbath in the coop.

Oh wait… that’s not right.

No – what I meant to say is that your best defense against heavy metal poisoning in your flock is knowledge. Having an awareness of potential dangers and keeping your eye out for areas on your property that could pose a danger to your birds is paramount.

If there is an area of known danger, do what you can to keep your birds away from it. Check old buildings for chipping paint, fence off areas where old motorized vehicles may have been sitting for long periods of time and keep hardware and fishing tackle away from your flock. Avoid exposing galvanized feed containers to the elements and pick up every last lucky penny you come across so your chickens don’t try to do it for you.

If you live on any land that has been occupied for many years, land that is near any kind of manufacturing plant, mine or land that has been used for dumping, consider having your soil tested.

And finally, keep an eye on your birds and be aware of their normal behavior so you can spot it if any seem “off.”

What can you do if you discover your birds have elevated levels of heavy metals? One can either cull these birds, or if you are willing to go to lengths to save them, chelation therapy can work to draw heavy metals out of the bird(s).

It would also be advisable to have your family tested if you have been eating the eggs of birds with high heavy metal levels.

Wishing everyone a great weekend!

- Leigh

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