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Other Names: 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. Chicks from hatcheries are most at risk.

When chicks hatch, their digestive tracts are virtually sterile. If raised by a mother hen, a chick obtains the beneficial microflora by consuming some of its mother's fecal material. In artificial incubation and brooding, chicks do not have this option. Therefore, baby chicks hatched in hatcheries are highly susceptible to different infections, and why all of the salmonella outbreaks that have occurred in humans in the United States have been linked back to chicks from hatcheries.

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


  • History
  • Clinical signs
  • Laboratory tests
  • Necropsy

Reported Cases

  • Case 1: Paratyphoid in a Canaries Necropsy and histopathologic examination revealed necrotic hepatitis and overall congestive septicaemia in carcasses. Salmonella enterica was isolated from 34 examined samples, two samples from each flock, including visceral organs of carcasses and droppings of live diseased birds. All isolates were typed as Salmonella enterica serovar Typhimurium by conventional serotyping. Antibiotic resistance profiling using 33 antibiotics and random amplification of polymorphic DNA differentiation by three primers were performed and showed an identical clonal relationship between these isolates and S. Typhimurium isolated from a sample of feedstuffs. Changing the feed ingredients along with antibiotic therapy via the drinking water by enrofloxacin solution controlled the outbreaks, and mortalities ceased. Ref


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.
AntibioticsAmpicillin, trimethoprim-sulfamethoxazole, or chloramphenicol
Probiotics and prebioticsAdded to dietH Al-Khalaifa et al., 2019; A Wolfenden et al., 2007
Thyme (Thymus vulgari) extract5 mg dried extract/mL (0.5% TVAE),V Elmi et al., 2020
Tumeric (Curcuma longa)0.1% in the feedD Hernandez-Patlan et al., 2019; K Varmuzova et al., 2015
Ashwagandha (Withania somnifera)0.5% of dietK Divua et al., 2015
Fermenting feedHelps chickens become less susceptible to Salmonella infection.L Heres et al., 2003
Baicalin (Scutellaria baicalensis) extract100-200 mg/kg of dietCui, Xiao-Die, et al 2023; Wang, Xian, et al. 2022; Zhang, Ling, et al. 2021; F Yang et al., 2020; Z Wu et al.,2020; Y Zhou et al., 2019; B Yin et al., 2021; M Bao et al., 2022; Z Hu et al., 2022



  • Ferment feed
  • Don't purchase chicks from hatcheries.
  • Avoid allowing chicks to drink from surface water instead of waterers
  • Minimize contact with wild birds or wild bird droppings
  • Control rodents
  • Give probiotics to young chicks.

Scientific References

Age Range

1 to 2 week old chicks are most susceptible

Risk Factors

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