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What is the best chicken bedding material choice? Which chicken bedding is the most absorbent? Opinions on chicken bedding absorbency are plentiful and vary widely in chicken forum posts and Facebook conversations. One issue with many of these opinions is they are anecdotal, based on a limited set of comparisons and not measurable. Based on this, we decided to do some real life testing on the absorbency of various common chicken bedding materials.

Of particular interest, which bedding would be most appropriate for the Deep Litter method of composting in place? For more information on how to set up a Deep Litter system read our article on Setting up a Deep Litter system.

Chicken Bedding Options

There are many widely used henhouse bedding materials. For our chicken bedding absorbency testing we selected 7 of the most common:

  1. Sand
  2. Sawdust
  3. Straw
  4. Pine Shavings
  5. Dried Leaves
  6. Horse Pellet Bedding
  7. Industrial Hemp
Hemp Bedding
Pine Shavings

It’s worth mentioning that horse pellet bedding is used either dry or pre-moistened.  When pre-moistened they expand into a sawdust like material.  For our testing we used them in their dry hard pellet form in Test 1 to allow for maximum absorbency. Test 2 we used the expanded material after allowing it to re-dry.

Sand Chicken Bedding:

Sand was rejected from the chicken bedding absorbency test for several reasons: First, sand has zero absorbency. Secondly, sand has no composting value. In a future article here on the blog we will post the pros and cons of using sand as a bedding method.

Why is Chicken Bedding Absorbency Important?

Chicken Bedding Absorbency is important for several reasons. Most importantly, some bedding materials don’t absorb moisture, or absorb and don’t dry out. Both of these factors create problems in a chicken coop. If you’ve been in a smelly chicken coop the most likely reason was too much moisture, or not enough ventilation. Excess moisture leads to increased ammonia being released from bedding. As a result, respiratory problems are created for the chickens and, in general, leads to a smelly coop. In addition, both wet litter and too much ammonia are the leading contributors to ulcerous lesions on chickens’ feet known as footpad dermatitis. Finally, excess moisture in bedding can attract flies and can cause mold. During our testing we observed that some containers full of moist bedding (just water – no chicken droppings) became swarmed by flies. Ideally it is beneficial to select a bedding material that will absorb moisture, wick it away from the surface and dry quickly.

Paw Lesions

Test Evaluation Parameters

Since we are evaluating chicken bedding materials for absorbency use in the henhouse there were two main criteria we were interested in:

  1. Dust profile – How dusty is the bedding and how messy is it to work with?
  2. Absorbency – How much moisture is the bedding material able to retain?

Dust was evaluated because at worst, with enough exposure it can be harmful to human’s and chicken’s respiratory systems. At best it is an irritant.

Dusty Chicken Coop

Dust Testing

For this test 1 lb of each bedding material was placed in a nylon stocking. Each stocking was manually shook up and down to measure dust output.  Since we don’t have the tools to measure particle sizes and counts this was a somewhat subjective test by observation.

Dustiness:

On a scale of 1-10 (10 being worst), the dust emitted by each bedding type was judged as follows:

  • Sawdust: 10
  • Straw: 5
  • Pine wood shavings: 3
  • Dried leaves: 2
  • Horse pellets (unmoistened form): 0
  • Industrial Hemp: 0

Messiness Factor:

Another point of comparison: The sawdust, straw and wood shavings all were particularly messy to work with, emitting a lot of spillage, particles and generally making a mess during general handling. The dried leaves, dried horse pellets and industrial hemp were not messy to work with.

Combining the Dustiness and Messiness Factor the following scores were assessed:

  • Sawdust: FAIL
  • Straw: FAIL
  • Pine wood shavings: FAIL
  • Dried leaves: PASS
  • Horse pellets (unmoistened): PASS
  • Industrial Hemp: PASS
Dusty Chicken Bedding

Chicken Bedding Absorbency Test 1 – Total Potential Absorbency

After checking the dust profile the next test was to see if the different bedding materials could absorb at least 3 times their weight in liquid. We utilized an absorbency test methodology similar to a study done by the University of Iowa. (Voyles, Reggie and Honeyman, Mark S. (2006) “Absorbency of Alternative Livestock Bedding Sources,”Animal Industry Report: AS 652, ASL R2153. ) First, each nylon was filled with 1 pound of the various types of chicken bedding.  Next, the samples were fully submerged in water for 24 hours. Finally, after 24 hours the samples were removed from the water and hung to drain for 75 minutes to allow excess water to drip out. After the 75 minutes the sample was weighed (minus the 1 lb of bedding) to measure the total weight of retained absorbed water.

Bedding Absorbency Test
University of Iowa Bedding Study

Absorbency Test 1 Results:

Results were as follows, showing total absorbed water weight.  Goal for a Pass was at least 3X absorption:

Bedding Type Absorbed Water Weight Moisture Holding Capacity Pass/Fail
Straw 3 lb 12 1/8 oz 375% PASS
Sawdust 3 lb 2 1/8 oz 313% PASS
Industrial Hemp 3 lb 1 3/8 oz 308% PASS
Pine Wood Shavings 2 lb 1 3/4 oz 210% FAIL
Horse Pellets 1 lb 15 oz 193% FAIL
Dried Leaves 1 lb 10 oz 162% FAIL

Chicken Bedding Absorbency Test 2 – Real Life Absorbency

The first test was interesting, but not reflective of real life. Animals are not submerging the entire amount of their bedding in liquid for 24 continuous hours. Also, although the total weight of each bedding sample in Test 1 was 1 pound, the volume of material varied widely. Subsequently, we needed to simulate the same volume of bedding as if it were in a henhouse or stall. Additionally, we needed to add a fixed amount of liquid like would happen if animals (chickens, horse, etc) were adding droppings or urine. Accordingly an absorbency test used was used similar to the methods used by the Department of Zoology at Oxford University to measure absorbency per unit volume. (Burns et al, 2005).

The second absorbency test began with a sample size of approximately 1 cubic foot of dry bedding was placed in a container and 8 cups of water were added. Next, the container was allowed to sit for 30 minutes then any excess water was poured off and measured. Pass criteria was that at least 90% of the liquid was absorbed by the bedding in 30 minutes.

Univ Oxford Bedding Absorbency
Water Pour Leaves

Absorbency Test 2 Results:

Here are the results of Test #2.  Pass criteria was at least 90% of the liquid absorbed.

Bedding Type Unabsorbed Liquid Amount Percentage Absorbed Pass/Fail
Sawdust 0 cups 100% PASS
Horse Pellets 0 cups 100% PASS
Industrial Hemp 1/2 cup 93.75% PASS
Straw 2.5 cups 68.75% FAIL
Pine Wood Shavings 3 cups 62.5% FAIL
Dried Leaves 5 cups 37.5% FAIL

After the second test was complete, as the sample containers were set aside, to our surprise a couple of the containers were immediately swarmed by flies. The sawdust, and moistened horse pellets had the biggest fly swarming. This seemed to be due to the high level of moisture they retained. It is interesting to note that a fly infestation around a chicken coop may be made worse by an excess moisture problem from a poor choice in bedding material. Subsequent follow up testing on different days showed this fly swarming was not 100% consistent, but it was interesting to observe so worth a mention.

Flies in Bedding

On a final note, we also observed the straw, sawdust and horse pellets took days to dry out.  We will do a more measured test on the dry time in a follow up post.

Chicken Bedding Absorbency: Summarizing everything

Sawdust Bedding:
  • Pros: Best absorbency. Some people can obtain for free.
  • Cons: Sawdust was by far the dustiest bedding material. In addition, it took several days to dry and became compacted when wet. The sawdust attracted many flies with just water added during the days that it dried. Finally, sawdust can be difficult for some people to source in large enough quantities for regular use as a chicken bedding material.
Straw Bedding:
  • Pros: Straw bedding is fairly inexpensive. Straw is easy to source as most for most chicken owners.
  • Cons: Straw is bit messy to work with. Furthermore, the straw bedding allowed a lot of liquid to pass through and settle to the bottom in Test 2. Straw takes a long time to dry. As a result straw can get moldy and smelly.
Dried Leaves Bedding:
  • Pros: Leaves can be obtained for free by almost anyone.
  • Cons: Dried leaves were not absorbent, allowing almost all the liquid in the second test to pass through. Consequently leaves did not absorb the liquid quickly.
Pine Shaving Bedding:
  • Pros: Pine shaving bedding is fairly inexpensive and available at many retail outlets.
  • Cons: The pine shavings allowed a lot of liquid to pass through and settle to the bottom in the second absorbency test and did not absorb it up quickly.
Horse Pellet Bedding:
  • Pros: Expanded horse pellets performed similar to sawdust and were very absorbent in the second absorbency test.
  • Cons: Horse pellets turn into sawdust once moistened. The pellets took a long time to dry – several days. As a result it seemed to attract a lot of flies while drying.
Industrial Hemp Bedding:
  • Pros: Industrial hemp bedding has no dust. The material was highly absorbent in both Test 1 and Test 2. Hemp absorbed almost all the liquid in real life Test #2
  • Cons: Upfront cost is higher, but one bale typically lasts for an entire year so total cost is the same or better than other bedding options.

So, what is the best chicken bedding material choice?

This analysis focused on chicken bedding absorbency. There are no “wrong choices” in choosing your bedding material from the options tested. All of the bedding choices will compost and can be used in a Deep Litter system. Some factors in choosing your chicken bedding should include:

  1. Is the material easy to source?
  2. What is the total cost of the chicken bedding on an annual basis?
  3. How quickly does the bedding material dry?
  4. Is the bedding material messy to work with?
  5. How dusty is the material?

Based on our measured testing Industrial hemp was the best chicken bedding when evaluating all the factors:

  • The industrial hemp had almost no noticeable dust emitted. Additionally, the hemp was not messy to work with when removing it from the bale.
  • Industrial hemp was 3rd in total absorbency (Test 1), barely getting beat out by sawdust and straw. However, Test 1 is not really representative of a real life simulation in a henhouse.
  • Hemp was highly absorbent in the 30 minute test (Test 2). Moreover, the hemp absorbed almost all 8 cups of water in the real life absorbency test (Test 2). It was narrowly bumped from 1st place by the sawdust products (sawdust and horse pellets).