Will all sand bedding kill your chickens? Silica and silicosis explained

People just don’t understand sand. Most people don’t even know what it is. But yet there is no shortage of chicken people out there on the internet telling you that sand will kill your chickens.

Recently, I got an email from a person who was brand new to chickens. She had read my article on pine shavings toxicity and told me it convinced her to stay away from pine. So far, so good.

She then said she was interested in using sand in her coop (still good), but then she was told by chicken people in forums that sand is toxic (aaaaand there we go).

She wrote to me, “Apparently, sand has silica in it, which is worse and will cause problems faster than any wood emissions. I have not been able to find a source of any sand guaranteed to be silica-free… Now I’m totally confused!”

To which, I thought, Yeah, you and pretty much everybody else.

This is not the first time someone has emailed me with these concerns—far from it. And with all the misinformation out there and misguided advice, how could it be any different?

So, let’s just get this straightened out right now. First, the short answer. Is all sand bad for your chickens?

Very fine-grained, airborne sand is dangerous for your chickens as it can lodge in their lungs, make them sick, and even kill them. Medium- to coarse-grained sand, however, isn’t airborne, and is, therefore, safe for your chickens.

Now, let’s get into it. As a former geologist who’s always looking for any excuse to talk rocks, I’m here to explain to you what sand is, what silica is, and why everyone thinks it will kill your chickens (and why it won’t).

You’ll learn what silicosis is, what silicate pneumoconiosis is, and whether you need to be concerned about your chickens developing these conditions.

You’ll learn what kind of sand I use and recommend, and why the scientific research suggests that sand is the best chicken coop bedding you’ll ever find.

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Sand, silica, silicosis, and silicate pneumoconiosis: Let’s get it straight.

What the heck is sand?

"Sand" is simply a word that refers to the grain size of particles only—it has nothing to do with mineral composition. 

"Sand" refers to grains of minerals or rock—of any composition—that are between 0.0625 and 4.75 millimeters in size.

And what the heck is silica?

Silica is a mineral. In fact, it's just quartz* (SiO2), which is an incredibly common mineral, found in a large percentage of rocks. In fact, if you were to just randomly pick a rock up off the ground, there’s a good chance you’d find quartz grains in it.

Quartz can also be found in the form of beautiful gems, such as amethyst, citrine, jasper, and agate. All these gems are just good ol’ silica.

Unlike the term “sand,” the term “silica” has nothing to do with grain size—silica can be microscopic in size or it can be gigantic. You may find one individual grain of silica, or you can find a rock made of several interlocking grains of silica. Silica simply refers to composition (SiO2). 

*Disclaimer: In the spirit of being accurate, not all silica is quartz, but the overwhelming majority of silica you find in sands is quartz. However, silica can come in non-crystalline (amorphous) forms, such as you see with opal, obsidian, or glass. But typically, when you hear people referencing “silica” as dangerous, they are talking about the crystalline form, quartz. 

What does silica have to do with sand?

Sand can be composed of minerals of any composition, depending on the rock it’s sourced from. Minerals that are commonly found in sand include calcite, feldspars, pyroxenes, amphiboles, micas, and, you guessed it, quartz (silica).

Most sands contain at least some quartz (silica) grains. Some sands are very high in quartz, like beach sand (not great for the coop), but others, like limestone sands, can be very low in quartz. Most sands are somewhere in between.

Why is everyone so afraid of silica?

Silica! Ooooooo! Scary!

Remember, silica is simply the scientific name for the common mineral, quartz (SiO2).

Sounds a little less scary when you just call it quartz, right? Let’s do that. 

It’s important to understand that the chemical makeup of quartz is not a problem. Quartz is a chemically inert mineral. Simply having contact with it doesn't cause any harm whatsoever. Playing with your amethyst crystals isn’t going to make you sick.

When quartz does become a problem is when it's inhaled and it gets lodged in your lungs—and that's not just quartz, by the way, that's other silicate minerals too (more on this below).

And the way quartz gets inhaled is when it's so fine-grained it becomes dust (i.e., grains that float in the air).

This is the main reason I don’t recommend you ever use play sand for your chickens. It's 100% quartz (unlike the majority of natural sands), and it’s simply too fine-grained. When play sand is disturbed, which can happen when your chickens walk or scratch on it, the sand releases dust that your chickens can inhale. 

And it's this dust that can cause silicosis (a lung scarring disease) or cancer over the long term.

This is also why sandblasters and others who work around airborne quartz wear protective gear—they’re either creating (or disturbing) fine-sand dust that can seriously damage their lungs.  

Does all silica cause illness in chickens?

The only way quartz dust can cause lung disease in your chickens is if they inhale it.

And this is why you want medium- to large-grained sands in your coop. These grains are too large to float as dust and they’re too large to be inhaled. Because they’re not airborne, they can’t cause the respiratory problems everyone’s so freaked out about. 

You can see photos below of the sand I use in my coops.

This sand is medium- to coarse-grained and it’s “washed.” This means the sand has been sprayed with water and sieved in order to remove the fine grains (you know, those ones that make your chickens sick).

You can see what this process looks like in the video below.

Washed sand is commonly sold by gravel companies. I purchased mine from my local gravel business.

But what about silicate pneumoconiosis? What causes that?

Surprise! It’s not just quartz, people!

There’s a whole long list of minerals that, when inhaled as dust, will cause lung disease. Micas and clay minerals, like illite, can be particularly brutal.

Whereas silicosis is specific to lung damage by quartz, silicate pneumoconiosis refers to lung damage by any silicate mineral.

What’s a silicate mineral, you ask? Silicate minerals are all the minerals containing silicon-oxygen compounds. So, yes, that includes our old friend, silica herself—quartz. But she’s not all.

Exactly how common are these minerals? There are hundreds of them, but only a few dozen are widespread. They do make up about 90% of the earth’s crust, though. Soooo…. pretty common, I guess.

The good news is, a lot of these minerals don’t appear to cause lung disease, even at fine grain sizes.

The great news is, like quartz, other silicate minerals can only cause disease if you inhale them. So, buying medium- to coarse-grained, washed sand will eliminate the great majority of these fine-grained particles. 

Where do I find medium- to coarse-grained, washed sand?

You’ll need to look at gravel companies to source your sand. Most of the sand you buy from big box stores is going to be too fine-grained.

When I made the choice to try sand, I called up my local gravel company and gave them the sand names I had read about from others online: construction sand, river sand, and bank sand. They had no idea what I was talking about.

They wanted me to give them the size in millimeters, but I had no clue. I guessed the grain size was around 0.4-0.5 mm long. They didn’t have anything that coarse, they said.

I visited the gravel company to see what they had available. The type of sand I wanted was actually labeled as way smaller than 0.5 millimeters, but it seemed to me like most of the grains were way coarser than what was labeled. So, I’m really not sure how they determined the grain size of their supply. This is why you really need to see the sand in person before buying. 

The photo below shows the sand I ended up buying. You can see it’s a mix of coarser- and finer-grained particles. If you still feel uncertain about what to order, print off this picture and take it to your local gravel company (or take a photo of it with your phone). They should be able to help you find the perfect sand. 

Here’s another great tip to make sure you get the perfect size of sand.

Bring a kitty litter scooper with you. You want your sand to be as coarse as possible, while still being fine enough that most of it will sift through your kitty litter scooper.

If your sand is so coarse it won’t fit through your scooper, you’re going to have a hard time cleaning the poop out of your sand. For more on this topic, see my article, Sand for chicken coop bedding: Pros, cons, and how to do it right.

Are all the fine-grained particles removed in washed sand?

The washing process will remove most of the smallest particle sizes from your sand, but you do need to be aware that even medium- to large-grained sands will have some dust when you first move them into your coop and when you clean your coop.

This is because these sands do still have some smaller grain sizes mixed in with the medium to large grains. As with all bedding types, make sure you wear an N95 mask or respirator when you clean the coop to prevent inhalation of the bedding.

You’ll want to wear sunglasses or goggles too. I make it easy and just wear a full-face respirator.

I also like to use a fan when I clean the coop. I leave the “people door” wide open, and set the fan in the doorway facing outwards. It sucks the dust right out, and I usually leave the fan there for 30 minutes or so after cleaning. This ensures my chickens won’t come back into the coop until long after all the dust has settled.

Can I be sure my chickens won’t get sick with medium- to large-grained sand bedding?

Is it possible that even the small amount of dust you get in your medium- to large-grained sands can cause respiratory damage in your chickens over many years? Yes, it’s possible.

There has been no research on this at all, unfortunately, so we just don't know. Believe me, I do so wish I could tell you otherwise.

However, the known risks of health problems with this type of sand for your chickens are much lower than the known risks that come with all other bedding types.

In the table below, you can see that the dust from the other two most popular bedding types, pine shavings and straw, also have some real potential problems associated with them.

Bedding Type	Effects of Dust	Sources
Pine Shavings	Liver and respiratory damage; cancer	Numerous – e.g., Ayars et al., 1989; Törrönen et al.,1989; Potgieter et al., 1995; Pelkonen and Hänninen, 1997; Demers et al., 1997
Straw	Bacterial, mold, endotoxin illnesses	Olenchock et al., 1990; see the review in Wichert et al., 2008; Siegers et al., 2018
Sand	Silicosis/silicate pneumoconiosis; cancer	Brambilla et al., 1979; Evans et al., 1988; Roperto et al., 2000; Lara, 2018

And below, you can see how sand stands up against pine shavings and straw in other important areas. Sand beats these other bedding types in almost every aspect measured. For more on this topic (and a buttload of research), see my article, The BEST chicken coop bedding: Sand vs. straw vs. pine shavings.

	Straw	Sand	Pine Shavings
Moisture Absorption	Excellent (Shepherd et al., 2017)	Poor (Bilgili et al., 2009)	Good (Shepherd et al., 2017)
Moisture Release	Poor (Shepherd et al., 2017)	Excellent (Bilgili et al., 2009)	Mediocre (Shepherd et al., 2017)
Cleanliness	Poor (Benabdeljelil and Ayachi, 1996)	Excellent (Bilgili et al., 2009)	Mediocre (Bilgili et al., 2009)
Ammonia Level	Medium (Tasistro et al., 2007)	Low to high (Bilgili et al., 2009)	Initially low (Tasistro et al., 2007)
Bacterial Load	Medium to High (Yarnell et al., 2016)	Low (Bilgili et al., 1999a)	Medium to high (Völkel et al., 2011)
Mold Load	High (Wichert et al., 2008)	Low	Medium to high (Tanner et al., 1998)
Dust	Medium to high (Fleming et al., 2008)	Low to high (Grimes et al., 2002)	Medium to high (Ward et al., 2000)
Additional Health Problems	Respiratory diseases (Wichert et al., 2008)	Silicate pneumoconiosis, cancer (Roperto et al., 2000)	Liver damage, respiratory damage, cancer (Pelkonen and Hänninen, 1997)
Ease of Use	Mediocre (Tasistro et al., 2007)	Poor (Garcês et al., 2013)	Excellent
Insulation	Warmer in winter with deep litter method	Cooler in summer (Grimes et al., 2002)	Warmer in winter with deep litter method
Composting	Excellent	Poor	Excellent
Flammability	Flammable (Ward et al., 2000)	Non-flammable (inorganic)	Highly flammable (Ward et al., 2000)
Insect Load	High (Schmidtmann, 1991)	Low (Schmidtmann, 1991)	High (Schmidtmann, 1991)

And if you want to see how sand stacks up against 18 other chicken coop bedding materials (spoiler alert: it’s ranked #1), see my article, A comparison of 21+ chicken coop bedding materials: The good, the bad, and the ugly.

It’s time we face the sad, sorry truth of raising chickens—bedding isn’t safe.

The sad truth is this: there is no perfect bedding.

Wild chickens were designed to roost in trees in the open air. When we force our chickens to live in coops with bedding, we are forcing them to do something unnatural (but of course, coops and bedding are necessary for the safety of our domestic chickens, so we have to do it). 

But all bedding materials are either subject to mold and other dangerous pathogen growth and/or to dustiness that may lead to respiratory problems.

The article I recommended above compares 21 bedding types. I literally read dozens upon dozens of academic papers on bedding to write this article. The sources cited at the bottom are a small sampling of everything I read. I read every single paper I could find on bedding.

And I found that every single bedding type out there has potential health problems. All bedding types are scary, and they’re all potentially dangerous.

Medium- to large-grained sand just has the fewest potential problems and is the least likely to harm your chickens. It’s the least scary of a scary bunch. That's why I recommend it.  

And now you have the facts too, so you can make up your mind for yourself. One last bit of advice: when it comes to issues of science, stay out of the chicken-keeping forums. Head to the academic journals instead.

For more info on sand and practical tips for using it in your coop, check out my article, Sand for chicken coop bedding: Pros, cons, and how to do it right.

Pin this article for later!

Sources

• Ayars, G., Altman, L., Frazier, C., and Chi, E., “The toxicity of constituents of cedar and pine woods to pulmonary epithelium.” Journal of Allergy and Clinical Immunology, v. 83, no. 3, 1989, p. 610-618.

• Benabdeljelil, K., and Ayachi, A., “Evaluation of Alternative Litter Methods for Poultry.” The Journal of Applied Poultry Research, V. 5, No. 3, 1996, P. 203–209.

• Bilgili, S., Montenegro, G., Hess, J., and Eckman, M., “Sand as litter for rearing broiler chickens.” The Journal of Applied Poultry Research, v. 8, no. 3, 1999a, p. 345-351.

• Bilgili, S., Hess, J., Blake, J., Macklin, K., and Saenmahayak, B., “Influence of bedding material on footpad dermatitis in broiler chickens.” The Journal of Applied Poultry Research, v. 18, n. 3, 2009, p. 583-589.

• Brambilla, C., Abraham, J., Brambilla, E., Benirschke, K., and Bloor, C., “Comparative Pathology of Silicate Pneumoconiosis.” The American Journal of Pathology, v. 96, no. 1, 1979, p. 149-169.

• Demers, P., Teschke, K., and Kennedy, S., “What to Do About Softwood? A Review of Respiratory Effects and Recommendations Regarding Exposure Limits.” American Journal of Industrial Medicine, v. 31, no. 4, 1997, p. 385-398.

• Evans, M., Slocombe, R., and Schwartz, L., “Pulmonary silicosis in captive ring-necked pheasants: definitive diagnosis by electron probe X-ray microanalysis.” Veterinary Pathology, v. 25, no. 3, 1988, p. 239-241

• Fleming, K., Hessel, E., and Van den Weghe, H., “Generation of Airborne Particles from Different Bedding Materials Used for Horse Keeping.” Journal of Equine Veterinary Science, v. 28, no. 7, 2008, p. 408-418.

• Gamble, J., “Silicate pneumoconiosis,” Occupational respiratory diseases, Merchant, J., Bochlecke, B., and Taylor, G., ed. Morgantown: U.S. Department of Health and Human Services, 1986, no. 86-102, p. 243-285.

• Garcês, A., Afonso, S., Chilundo, A., and Jairoce, C., “Evaluation of different litter materials for broiler production in a hot and humid environment: 1. Litter characteristics and quality.” The Journal of Applied Poultry Research, v. 22, no. 2, 2013, p. 168-176.

• Grimes, J., Smith, J., and Williams, C., “Some alternative litter materials used for growing broilers and turkeys.” World’s Poultry Science Journal, v. 58, no. 4, 2002, p. 515-526.

• Lara, A., “Silicosis.” Merck Manual Professional Version, March 2018.

• Olenchock, S., May, J., Pratt, D., Piacitelli, L, and Parker, J., “Presence of endotoxins in different agricultural environments.” American Journal of Industrial Medicine, v. 18, no. 3, 1990, p. 279-284.

• Pelkonen, K. and Hänninen, O., “Cytotoxicity and biotransformation inducing activity of rodent beddings: A global survey using the Hepa-1 assay.” Toxicology, v. 122, no. 1-2, 1997, p. 73-80.

• Peters, J., “Silicate pneumoconiosis,” Occupational respiratory diseases, Merchant, J., Bochlecke, B., and Taylor, G., ed. Morgantown: U.S. Department of Health and Human Services, 1986, no. 86-102, p. 219-237.

• Potgieter, F., Törrönen, R., and Wilke, P., “The in vitro enzyme-inducing and cytotoxic properties of South African laboratory animal contact bedding and nesting materials.” Laboratory Animals, v. 29, no. 2, 1995, p. 163-171.

• Roperto, F., Borzacchiello, G., Ungaro, R., and Galati, P., “Silicate pneumoconiosis in hens.” Journal of Comparative Pathology, v. 122, no. 4, 2000, p. 249-254.

• Schmidtmann, E., “Suppressing immature house and stable flies in outdoor calf hutches.” Journal of Dairy Science, v. 74, no. 11, 1991, p. 3956-3960.

• Shepherd, E., Fairchild, B., and Ritz, C., “Alternative bedding materials and litter depth impact litter moisture and footpad dermatitis.” The Journal of Applied Poultry Research, V. 26, no. 4, 2017, P. 518–528.

• Siegers, E., Anthonisse, M., van Eerdenburg, F., van den Broek, J., Wouters, I., and Westermann, C., “Effect of ionization, bedding, and feeding on air quality in a horse stable.” Journal of Veterinary Internal Medicine, v. 32, no. 3, 2018, p. 1234-1240.

• Tanner, M., Swinker, A., Beard, M., Cosma, G., Traub-Dargatz, J., Martinez, A., and Olenchock, S., “Effect of phone book paper versus sawdust and straw bedding on the presence of airborne gram-negative bacteria, fungi and endotoxin in horse stalls.” Journal of Equine Veterinary Science, v. 18, no. 7, 1998, p. 457-461.

• Tasistro, A., Ritz, C., and Kissel, D., “Ammonia emissions from broiler litter: response to bedding materials and acidifiers.” British Poultry Science, v. 48, no. 4, 2007, p. 399-405.

• Törrönen, R., Pelkonen, K., and Kärenlampi, S., “Enzyme-inducing and cytotoxic effects of wood-based materials used as bedding for laboratory animals. Comparison by a cell culture study.” Life Sciences, v. 45, n. 6, 1989, p. 559-565.

• Völkel, I., Schmitz, C., Moors, E., Gauly, M., and Czerny, C., “Frequency of Salmonella detection in a broiler flock depending on different litter materials--a field study.” Berliner und Münchener tierärztliche Wochenschrift, 2011, v. 124, no. 1-2, p. 71-77.

• Ward, P., Wohlt, J., Zajac, P., and Cooper, K., “Chemical and physical properties of processed newspaper compared to wheat straw and wood shavings as animal bedding.” Journal of Dairy Science, v. 83, no. 2, 2000, p. 359-367.

• Wichert, B., Nater, S., Wittenbrink, M., Wolf, P., Meyer, K., and Wanner, M., “Judgement of hygienic quality of roughage in horse stables in Switzerland.” Journal of Animal Physiology and Animal Nutrition, 2008, v. 92, no. 4, p. 432-437.

• Yarnell, K., Le Bon, M., Turton, N., Savova, M., McGlennon, A., Forsythe, S., “Reducing exposure to pathogens in the horse: a preliminary study into the survival of bacteria on a range of equine bedding types.” Journal of Applied Microbiology, 2016, v. 122, no. 1, p. 23-29.