Ammonia Toxicity in Chickens

Reviews etiology, risk factors, clinical signs, prevention, and treatment.
By Melky · Oct 25, 2018 · ·
  1. Melky
    Ammonia Toxicity In Chickens


    Ammonia is naturally produced in poultry droppings and has a very pungent smell. Besides the challenge of a smelly coop, did you know that ammonia levels could build up in your coop without proper ventilation especially during the winter months when it is cold outside and everyone wants to close the chickens up inside the coop for warmth? Did you know that ammonia is an invisible, water-soluble, colorless alkaline gas and is listed as a toxic substance by the Agency of Toxic Substances and Disease Registry? Ammonia can also be found in common household or industrial cleaners such as window cleaning products and also some pesticides.

    Humans and chickens after repeated or prolonged exposure can develop reduced sensitivity to the odor of ammonia but the harmful effects can still lead to a chronic sinusitis. The ammonia odor can be an eye, mucous membrane, and respiratory irritant. As we prepare our coops it is important to think about types of bedding, frequency of manure removal, humidity level, surface area of stored manure, ventilation, manure handling, number of chickens, and the pH of the manure.

    Ammonia toxicity is noted by an inflammatory eye condition usually bilaterally in chickens, caused by exposure to prolonged or high amounts of ammonia fumes. It has been found that ammonia concentrations above 25 ppm are toxic to chickens and some have concern for toxicity or irritation at 10 ppm. The ammonia concentration (AMC) is higher in the morning and at night when the wind is not blowing and the heat index is extreme. Typically temperatures above 25°C (77° F) and humidity > 80% increase AMC levels. The main presenting symptom is conjunctivitis an inflammation of the cornea and conjunctiva of the eye. Younger chickens are of course more susceptible than adult chickens and this is more frequently seen in the winter time due to increased time spent inside, with reduced ventilation, and accumulated manure. Many anticipate evaporative moisture losses assist in removal of moisture from litter but evaporation rates may be inadequate to remove quantity of water added to litter on daily basis from manure and drink spillage, which compounds the problem. If pH is 7 or greater this also will allow for conversion of ammonium to ammonia so reducing pH of litter to less than 7 becomes important.

    Cases of Ammonia Toxicity reported in flocks
    Ammonia Toxicity Chart.jpeg
    Clinical Signs

    Crusty eyes
    Swollen eyelids
    Rubbing heads against wings
    Gray-cloudy looking cornea
    Reddened eyes
    Sensitive to Light

    Clinical signs
    Eye exam

    • Improve Management Practices
      Clean and change coop litter more often; consider switching to a different type of material. Peat works best for reduction of ammonia levels.
    • Supportive Care
      Isolate the bird from the flock and place in a safe, comfortable, warm location (e.g. chicken hospital or covered crate) with access to water and food. Limit stress. Call your veterinarian.
    • Topical Antibiotics
    Risk Factors
    Build up of droppings in an enclosed area
    Poor ventilation
    Increased Moisture
    Increased time indoors, particularly the winter

    • Add 100 g/kg of natural zeolites (clinoptilolite) to the bedding litter, to reduce moisture, ammonia levels, and pH
    • Ensure proper ventilation and provide dry, clean bedding that is frequently changed
    • Do not overcrowd birds
    Product Resources
    DooKashi Coop Odor Eliminator: ie=UTF8&tag=dvmsites20&creative=9325&linkCode=as2&creativeASIN=B010TXIY1Y&linkId=f8c28bb7d46951c0cd3d5d44792c1596


    Manna Pro Coop Odor Eliminator:


    Sweet PDZ Coop Refresher:

    Depends on timeliness of diagnosis and treatment.

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    Arteaga, V., Mitchell, D., Armitage, T., Tancredi, D., Schenker, M., & Mitloehner, F.
    (2015). Cage versus noncage laying-hen housings: Respiratory exposures.
    Journal of Agromedicine, 20(3), 245-255.

    David, B., Mejdell, C., Michel, V., Lund, V., Moe, R.O. (2015). Air Quality in
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    Dunlop, M.W., Blackall, P.J., & Stuetz, R.M. (2015). Water addition, evaporation and
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    Gutiérrez-Zapata, D.M., Galeano-Vasco, L.F., Cerón-Muñoz, M.F. (2016).
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    Poultry DVM. (2018). Ammonia toxicity. Retrieved from

    Schneider, A.F., Almeida, D.S., Yuri, F.M., Zimmermann, O.F., Gerber, M.W., &
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    Science, 57
    (2), 257-263.

    Shah, S., Westerman, P., & Parson, J. (2012). Air quality; Poultry litter amendments.
    Air Quality Education in Animal Agriculture. The USDA National Institute of Food
    and Agriculture. Retrieved from
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    U.S. National Library of Medicine. (2014). Ammonia. Tox Town. Retrieved from

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    About Author

    Hi, I am striving to always lead an organic happy healthy life for me and my family supporting farm to table excellent quality food. I love going in my backyard to find what is for dinner combining the best of flavors for that perfect taste and aroma to put on my plate.

Recent User Reviews

  1. khind
    "Important, Useful Information"
    5/5, 5 out of 5, reviewed Jan 20, 2019
  2. lcwmt
    "instructive article on a Winter risk factor"
    5/5, 5 out of 5, reviewed Jan 19, 2019
    Top notch! I appreciate the documentation and the way you organized your information. You tell us what why and how - in regard to effects of the problem as well as how to prevent/avoid it. thank you.
  3. JerryR708
    "Helpful article"
    5/5, 5 out of 5, reviewed Jan 18, 2019
    I enjoy cleaning my coops and collecting poop for my compost, so hopefully I won't have to worry about ammonia levels. I learned something new and what to avoid in the future with this helpful article.


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  1. copper2
    What about cleaning the coop with ammonia....
    1. Melky
      Cleaning coop with ammonia is not recommended. Usually 10% bleach solution or 50/50 vinegar and water. I use the 50/50 vinegar and water.
  2. townchicks
    Good info. I knew ammonia could cause respiratory problems, but wasn't aware of the eye concerns. Thanks.
      Melky likes this.
  3. Melky
    As I wrote this article many chicken keepers had questions for winterizing coops which made me think do people really know why it is important to reduce ammonia, moisture, and pH and how you do it. This is particularly important to do in winter but also throughout the year to eliminate disease. While other articles described the structure of a coop and ventilation, we really had not discussed bedding or odor elimination products that work. This article lets you know proven methods through research that work.
      MiroKoop and townchicks like this.

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