Ammonia Burn Keratoconjunctivitis i ...

Ammonia Burn Keratoconjunctivitis in Laying Hens

Ammonia Burn Keratoconjunctivitis, Ammonia Fumes (High Levels 50 to 75 ppm or greater than 100 ppm) persistent in Laying Hens

Ammonia burn describes conjunctivitis in poultry caused by exposure to ammonia fumes resulting from unsanitary conditions. (1, 2)

Ammonia levels should be less than 25 ppm, but in poorly ventilated litter-type houses, ammonia exceeds 100 ppm. (1, 2)

High levels of ammonia (50-75 ppm) reduce feed consumption and growth rate. Egg production is also reduced and conjunctivitis occurs. If levels greater than 100 ppm persist, corneal ulceration and blindness can occur. At levels of 75-100 ppm, changes in respiratory epithelium occur such as loss of chilli, and increased numbers of mucus-secreting cells. Heart rate and breathing may be affected, and there may be hemorrhages in the trachea and bronchi. (1, 2)

Clinical signs include photophobia, excessive lacrimation, and respiratory congestion. Affected birds keep their eyelids closed and are reluctant to move. They may rub their heads and eyelids against their wigs. The cornea has a grey cloudy appearance and may be ulcerated. Edema and hyperemia may be present in the conjunctiva but often may not be very obvious. The condition is generally bilateral and affects birds which do not eat and become emaciated. (1, 2)

Observed Clinical Signs Happenings

Egg Drop

  • Egg production declines gradually
  • Drop in egg production may be affected and depends on the severity of the exposure to ammonia fumes

Visibly sick birds

  • Few visibly sick birds
  • Birds may rub their head and eyelids against their wings

Eyes affected

  • Affected birds keep their eyelids closed
  • They rub their heads and eyelids against their wings
  • The cornea has a grey cloudy appearance and may be ulcerated
  • Edema and hyperemia  may be present in the conjunctiva
  • The condition is generally bilateral
  • Affected birds do not eat and become emaciated

Feed Consumption Changes

  • Feed intake reduced (sometimes difficult to measure)

Internal Egg Quality

  • Watery White or White Haugh unit decreased score (should be 70 poor 50)
  • Yolk Mottled or Flecked or Flaccid and Fragile (a very limited amount of mottling is normal)

Ammonia Burn Keratoconjunctivitis, Ammonia Fumes (High Levels 50 to 75 ppm or greater than 100 ppm) persistent in Laying Hens DOES NOT exhibit or manifest any of the following clinical signs happenings:

  1. Egg drop
  2. Mortality above the standard
  3. Flock behaviour activity change
  4. Droppings abnormalities
  5. Respiratory abnormalities
  6. Neurological Nervous
  7. Lameness or unusual movements, incoordination, ataxia
  8. Head, Comb, Wattles, Face, Nostrils, Sinuses, Mount, Beak, Earlobes, abnormalities
  9. Body Parts (Neck, wings, breast, abdomen, shanks, legs, hocks, feet, joints, vent, and skin) abnormalities
  10. Feathers abnormalities
  11. Diet or Feed Changes
  12. Shell quality defects
  13. Internal Egg defects
Causing Agents
Toxicity, due to high concentrations of atmospheric ammonia in enclousure or litter
Affected Systems/Organs
Respiratory System: Eyes (even low but constant exposure to 10-20 ppm ammonia is enough to cause some damage to the respiratory tract)
Mainly Affects
Performance: It could act as trigger for respiratory tract infections/complications
Appropriate environmental control. Prevention of the condition is based on proper ventilation and litter management. The ammonia fumes are formed in wet litter. Feed additives and ammonia reducing agents
Suggested Actions
  • Can be confirmed with clinical signs and gross lesions
  • Can be dealt with in house
  • Technical assistance recommended
  • Can be managed with feed additives, off-the-shelf medications

Impact on Egg quality


Impact on Liveability


Impact on Production


Overall Economic Impact


  1. Y.M. Saif. 2008. Disease of Poultry. 12th Edition. page 1178
  2. David E. Swayne. 2013.  Diseases of Poultry 13th Edition. page 1258
  3. Mark Pattison, Paul F. McMullin, Janet M. Bradbury. Dennis J. Alexander. 2008. Poultry Diseases. 6th Edition.
  4. Paul McMullin. 2004. A Pocket Guide to Poultry Health and Disease. First Edition.
  5. Steven Leeson, John D. Summers. 2008. Commercial Poultry Nutrition. Third Edition.
  6. Donald D. Bell, Williams D. Weaver. 2009.  Commercial Chicken Meat and Egg Production. Fifth Edition.
  7. Gail Damerow 1994. The Chicken Health Handbook.




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