Friday, March 8, 2013

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 article in 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:

Failure to grow or to maintain weight
Loose stools – greenish-black in color
Lack of balance
Inability to perch
Brain function disturbance
Loss of coordination
Loss of vision
Inability to hold head straight

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)
Kidney, liver and pancreatic anomalies

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


  1. Great article! can never play too much AC/DC, Metallica or Black Sabbath in the coop!
    Rock on, Ladies!

  2. I'm wondering about metal siding and roofing used on pole building type barns. Have you come across any information on what may be leaching from the metal siding/roofing?

    We have a pole building on the property that has been here about 20 years that has faded and the roof was just repainted. Wonder what might be in the ground around it from weathering?

    1. Zinc is the biggest concern with older metal buildings. Here is a link to an at-home soil test kit that detects a variety of heavy metals: Test Kit

    2. I had never considered galvanized before on the feeding pans and chick feeders. I wonder how much is leached into DRY FOOD in a galvanized pan?

      The next thing I'd like to hear is how does RUBBER affect chickens? I'm thinking of those large rubber feed pans. I've always wondered about the fumes from rubber too.

      I have a rubber floor mat on the people side of the coop to scrape my feet on when I come out. It is a mat that had set outside in the fresh air for several months before moving it into the hen house so there are virtually no fumes at this point. However, I have another small mat that sits under one of the feed bowls that gets feed on it and they peck on it to pick up the dropped feed.

      I've moved to using GLASS (Pyrex or Anchor) pie pans for feed pans. They're heavy enough that they don't get knocked over and were shallow enough for the chicks to eat from.

  3. I hadn't thought about this before and now I'm aware. Never too old to learn! Thank you.

  4. Great informative post! Thanks for sharing- had never crossed my mind..... what's helpful is the s/s exhibited from chickens with either toxicity.

  5. Does putting ACV into a galvanized waterer leach zinc into the water?

    1. In some of my reading, I have read to never use ACV in the galvanized waterering vessel. I will reference the book "The Chicken Whisperer's Guide to Keeping Chickens" by Andy G. Schneider and Dr. Brigid McCrea, Ph.D. page 111 in the Note at the bottom of the page: "NEVER put apple cider vinegar in galvanized waterers---it will react with the metal and harm the chickens.

    2. That's correct! It can leach zinc into the water. There is an article here on the blog about the metals to watch out for.

  6. I didnt even consider my feed dishes to be a possible issue. I have been giving my chicks FF in a galvanized feeder for about a week :( Should I be terribly concerned or just switch the containers for a different material and assume they are fine? They seem to be acting fine.

    1. I would just switch since it's just been a week. They should be okay!

  7. Thanks for the info. It will surely help spread awareness with regard to the hazards that these metals can bring to a person. One would think that they are safe from lead poisoning by avoiding too much exposure to the chemicals, without knowing that it could be in the things that they eat.

    Leora Yang @ Environmental Diseases

  8. Great article,
    I recently saw a warning on chicken wire and hardware cloth sold in California that said it contained lead. Do you know anything about the safety of this.

    1. I have not heard about that and I don't see anything on it from any valid sources. If you know where you saw the warning, you might want to ask the source and ask where they got their information.


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