Most chicken coops are made of wood, and all wood eventually rots. You can deal with this fact in a number of ways:
- Build with wood that’s infused with pesticides (pressure-treated “PT”)
- Use a naturally rot-resistant wood (like cedar, redwood, or tropical hardwoods)
- Choose a softwood (like Douglas-fir, hemlock, or pine) and apply a sealer
- Use a composite material instead of wood
Many factors will weigh into your choice, but I’ll deal with the two biggies: toxicity and cost.
Toxicity
Treating lumber with a non-toxic preservative
Anything put into or onto wood may find its way into your chickens, then into you. This makes PT generally a poor choice. The EPA advises against using any kind of PT “in circumstances where the preservative may become a component of food, animal feed, or beehives.” (One exception to this may be YellaWood®, available in the South. Its manufacturer claims that it is an environmentally preferable product because of the special way it’s treated. I don’t have personal experience with it to give an opinion.)
As for sealers, choose carefully to avoid toxic ingredients. Personally, I like the products from TimberPro Coatings. Ecohaus in the Pacific Northwest also offers some safe options for exterior use, including the brand Osmo. Finally, using naturally rot-resistant woods gets you around the toxicity problem altogether, but leads to the second issue. . .
Cost
Let’s start with cedar. It’s pricey, and while praised for its rot-resistance, this characteristic is true more of the heartwood than the sapwood. Two local lumber stores told me that most available cedar comes from second-generation forests and lacks the longevity of old-growth heartwood. Both steered me away from it, saying that you’d have to seal it, and if you’re sealing it anyway, you might as well use cheaper softwood. Other costly options include the composite material used for decks and FSC-certified tropical hardwoods, both of which are more expensive than cedar, yet can last unsealed for decades.
The best choice?
I’m not sure. But I can share some principles:
- Mix materials based on how exposed they’ll be in your finished product, investing in longer-lasting materials where it pays to do so.
- Remember that once you attach hardware cloth to the wood, you will likely never get the chance to seal it properly again.
- Use a non-toxic preservative such as Internal Wood Stabilizer from TimberPro UV on any unsealed softwoods.
- Build so that you can replace pieces without having to dismantle the whole coop. This way, a rotten board every few years isn’t such a big deal.
- Remember that the best wood may be what you can reclaim from another project. Make sure it is free of toxic paint, seal it up, and you’re good to go.
- The perfect is the enemy of the good. Don’t let your search for the ideal materials or design get in the way of building something. After all, it’s just a chicken coop!
