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Weak Chicks

Paratyphoid (PT) is an important bacterial disease of chickens worldwide. It is one of several types of diseases caused by infection with Salmonella species. The outcome of exposure to Salmonella is influenced by a variety of factors which include the chicken's age, general health, level of nutrition, breed, and whether they had any earlier exposure to the disease that might have allowed the bird to develop a natural immunity. Management and environmental factors that cause stress to the bird, such as overcrowding, concurrent parasitic infections, improper or poor diet, getting picked on by other birds, left out in the cold, etc. all compromise the birds’ ability to resist infection, and increase vulnerability to developing clinical disease.

How Paratyphoid is Transmitted

PT is transmitted to chickens multiple ways, however it is typically through other apparently healthy or recovered chickens that serve as carriers of the Salmonella bacteria. Infected birds will shed Salmonella in their droppings, which in turn contaminate the environment, where they will survive and multiply. This is why it's important to regularly clean the environment of where chickens are kept, because accumulation of droppings can lead to high levels of the organism in the environment. Salmonella favors damp, warm conditions, where they can continue to replicate and survive for extended periods of time, without good management practices and regular cleaning occurs.

How Paratyphoid is Diagnosed

Paratyphoid is diagnosed in chickens through the identification of the presence of the Salmonella bacteria associated with disease. Simply detecting the presence of Salmonella here is not a diagnosis of paratyphoid. The two most common tests performed for your veterinarian to obtain a diagnosis are:
  • Bacterial culture: Using a swab, your veterinarian will obtain material from the suspected site, either internally (from a dead bird during a necropsy), or from the chicken's cloaca, throat, droppings or surgery site. Once collected, the swab is sent off to a diagnostic lab where it is cultured (i.e. grown) and bacteria identified. A follow up antibiotic sensitivity test is also useful in order for your veterinarian to determine which antibiotic will be most effective against the organism.
  • Antigen Detection Test: A simple test which detects the presence of protein on the surface of the bacteria. The sample can be obtained during a necropsy on a dead chicken or from a live bird.

Clinical Signs

Loss of appetite
Increased thirst
Huddling near neat source
Pasty butt
Swollen eye(s)
Droopy wings
Constant chirping noises
Head down with eyes closed
Reduced egg production
Swollen joints
Purplish-colored comb/wattles


  • History
  • Clinical signs
  • Laboratory tests
  • Necropsy


Supportive careIsolate the bird from the flock and place in a safe, comfortable, warm location (your own chicken "intensive care unit") with easy access to water and food. Limit stress. Call your veterinarian.



  • Avoid allowing chicks to drink from surface water instead of waterers
  • Minimize contact with wild birds or wild bird droppings
  • Control rodents
  • Provide apple cider vinegar in drinking water

Scientific References

Good Overviews

Age Range

1 to 2 week old chicks are most susceptible

Risk Factors

  • Poor sanitation
  • Chilled brooder
  • Contamination of environment with wild bird or rodent feces
  • Overheating