Keeping chickens on contaminated soil

You’re ready to get chickens, you’re totally pumped. And then you do some soil tests (just to be safe) and discover you have high levels of lead in your soil.

Bugger.

So what do you do – turn around, relinquish your hopes of having a feathered flock of your own and suppress the urge to cry? Wrong, you get informed, do a good design and work out a strategy, because there is always a way.

But first, what is lead and why all the fuss? Lead is a heavy metal which, if ingested, is poisonous to animals and humans (especially babies and small children). It damages the nervous system, can cause brain disorders and compromise brain development. The other major downer is that it does not ‘break down’ and leave your system, instead it accumulates in both soft tissues and bones. So chickens, who love to scratch, peck and eat soil, can ingest lead and pass a large portion of it straight into their eggs.

Where does lead come from?? It usually finds its way into our soils in the form of old flaky house paint. Up until the 1970s house paint consisted of 50% lead – ouch. These days house paint has around 0.1% – you can read all the facts and figures about it here.

lead paint

The other common way it’ll find its way into the soil is through petrol runoff, think busy roads and inheriting homes and gardens which used to belong to mechanics or wanna-be mechanics.  Car graveyards, old sheds and oily puddles are good indicators of lead being in the soil. But of course, always get it tested if you’re suspicious.

petrol image

So, now to the designing bit. One option is to scrape your site of all the contaminated soil and replace the whole lot with new stuff, yes – this quickly adds up and empties your piggy bank. But it is an option.

Another approach is to work with what you have. You can literally cover your contaminated soils with geo-fabric to seal it soil off. Then, add a layer of shade cloth on top as extra reinforcement and to prevent chickens from trying to scratch through the geo-fabric. Finally, add a deep litter layer of either straw, woodchips or another type of mulch substance for the chickens to scratch, play and live in.

chook lead diagramThis low-tech system is highly effective in providing a safe, healthy and happy space for your chickens to live in. The top layer of straw/mulch provides the deep litter the chickens need to have their dust baths, soak up their poo and ultimately transform into compost. You’ll need to replace this mulch once or twice a year to keep things fresh. And of course, the stuff you scrape out of there is more valuable than gold – seriously, it has major life giving properties for your food production spaces.

Our friend Margaret has some heavy lead contamination in her soils in urban Hobart. After a good year of research, thinking and learning she now has 3 small bantams, Snowflake, Nugget and Purple (she let her grandchildren name them). Margaret is smart – really smart, and has started small, both with the size of her chickens and the house she has built for them as she wants to make sure she’s got a good system before expanding their set-up.

chook shed

Despite having lead contaminated soils, Margaret has been able to apply good design to integrate chickens into her garden

After excavating the contaminated soil out of one area she lined it with weed mat and placed a deep litter layer on top. It’s totally fine that she hasn’t used geo-fabric and shade cloth as we suggest in our above diagram, the weed mat will do the same job – we just outlined a bomb proof option to be super safe.

Now Margaret’s happy with the system, she’s planning on extending the run to provide more space for her bantams to stretch their legs. FYI, each chicken likes to have a minimum of 2 square feet of floor space inside their house. Outside, give them a minimum of 10 square feet  per bird. You can read lots more about chickens and their needs at Backyard Chickens.

chook house.1

Snowflake keeping a safe distance from me while I check out her lil’ home.

chook house.2

A close up of the chicken house. The black weed mat is providing a protective layer between the contaminated soil and the chicken’s mulch layer.

While Margaret’s system is quite small, this design solution can be up-scaled significantly. Depending on your capacity and budget, it could easily be applied to 1/4 acre block if required.

MORE INFORMATION & RESOURCES

Photo credit to Kirsten Bradley from Milkwood Permaculture for our cover photo, thanks for photographing our chickens :-).

*Your blogger is Hannah Moloney: Co-director of Good Life Permaculture and lover of all things fun and garden-esk

4 Responses to “Keeping chickens on contaminated soil”

  1. Thomas

    Hi Hannah
    Two foot is really a very deep litter. We’ve got about 10cm, which is 1/6th of your suggestion, and our chickens haven’t scratched down to expose the weed mat anywhere. We’re using wood chippings, from the council, for the deep litter, and it’s working well so far. T

    Reply
    • Hannah Moloney

      Hi Thomas,
      We suggest having a deeper one for two reasons.
      1) Some chickens will scratch more vigorously than others (isa browns, rhode island reds) and dig deeper than smaller chickens (fluffy small bantams), so in that regard it’s a precautionary approach to take.
      2) The other reason we suggest this is that the deeper it is, the more biology will be attracted to that environment. You’ll also have a fairly balanced moisture level and a plethora of bugs moving in, this means more food for chickens and you also happen to be making a slow compost a the same time – yay! Some people actually recommend putting in one metre (or more) worth of mulch for this reason, especially when you’re not rotating your chickens around to different/fresh ground.
      So while it’s not always critical – it’s a way to either take precaution or create multiple benefits from one system, which we just love advocating for.
      Thanks for your comment :-).

      Reply
  2. Margaret Steadman

    Very chuffed to see my girls feature in your blog, Hannah. Since you took those photos, I’ve moved them to another spot in the garden which is easier for me to get to and made them an extra run by digging out some contaminated soil and using geotextile this time around to line all the areas. I reckon I’ve given them about 40 cms of straw which I top up regularly. I dig out most of the straw and the lovely composted soil at the bottom about 3 or 4 times a year and put in the compost bin or straight onto the garden. The chooks are very healthy and lay well.

    Reply

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