United States Department of Agriculture • Animal and Plant Health Inspection Service • Safeguarding American Agriculture 

Veterinary Services 

Centers for Epidemiology and Animal Health October 2012 

_________________________________________________________________________________________________________________________ 

E. coli Peritonitis on BreederChicken Farms in the United 

States 

Breeder-chicken farms consist of primary breeders, 

whose progeny are breeding birds, and multipliers, 

whose progeny are broilers and table-egg layers. 

Breeder farms provide the genetics for the poultry 

industry, and the birds on these farms are very valuable. 

Therefore, disease can have a substantial economic 

impact in these flocks. 

Escherichia coli are normal inhabitants of intestinal 

tracts and can be found in chicken feces, litter, dust, and 

rodent droppings. It may also contaminate feed and 

water (Barnes, 2008). E. coli is the most common 

bacteria recovered from birds affected with peritonitis, an 

infection of the lining of the abdominal cavity (Barnes, 

2008; Beckman, 2006). E. coli is frequently a secondary 

infection; tissues damaged by viral infections are 

susceptible to secondary bacterial infections. Earlyproduction E. coli peritonitis in breeder flocks is often 

related to the onset of egg production and can be 

secondary to respiratory disease. Late-production 

infections are often related to vent trauma. 

The USDA’s National Animal Health Monitoring 

System (NAHMS) conducted a study of U.S. breederchicken farms in 2010. A total of 482 breeder farms 

located in the Central region (n=107) and East region 

(n=375) of the United States participated in the study 

(see map below). The 482 farms consisted of 291 meattype (broiler) multiplier farms, 117 meat-type (broiler) 

primary breeder farms, 61 table-egg-type multiplier 

farms, and 13 table-egg-type primary breeder farms. 

The study focused primarily on breeder-farm biosecurity. 

Occurrence of E. coli peritonitis 

Breeder farms placed hens in the laying house at 

20.9 weeks of age and removed them at 64.1 weeks of 

age, on average. Breeder farms reported the occurrence 

and severity of E. coli peritonitis in the last completed 

flock: 22.7 percent of all breeder farms had a slight, 

moderate, or severe problem in the last completed flock. 

About two-thirds of primary breeder farms (67.7 percent) 

had a slight, moderate or severe problem with E. coli

peritonitis in the last completed flock (see figure below). 

Although data regarding specific causes of mortality 

were not collected, cumulative flock mortality to 

60 weeks of age increased with degree of E. coli

peritonitis problems. Flocks with moderate/severe E. coli

peritonitis problems had an average mortality of 

16.4 percent compared with 13.6 and 9.8 percent for 

flocks with slight and no problems, respectively. 

FL

NM

DE MD

TX OK

KS

NE

SD

ND

MT

WY

CO

UT

ID

AZ

NV

WA

CA

OR

KY

ME

NY

PA

MI

VT NH

MA

RI CT

VA

WV

OH IN

IL

NC

TN

SC

MS AL

AR

LA

MO

IA

MN

WI

NJ

GA

Poultry 2010 Regions*

Regions 

East 

Central 

*Companies reported farm location by region, not by individual State.

0 20 40 60 80 100

Central

region

East

region

Primary

breeder

Multiplier

Broiler

breeder

Egg-type

breeder

Percent

Severity

Percentage of breeder farms by severity of 

E. coli peritonitis problem in the last completed 

flock, and by demographic

All breeder

 farms

Severe

Moderate

Slight

None

Demographic

Technical Brief 
United States Department of Agriculture • Animal and Plant Health Inspection Service • Safeguarding American Agriculture 

Risk factors associated with E. coli peritonitis

Peritonitis in breeder chickens is most often 

associated with the onset of sexual maturity and egg 

production. Body weight, flock uniformity, lighting, feed 

allocation, temperature, and ventilation are important 

factors in the disease (Merck 2010). These factors, 

however, were not addressed in the NAHMS study, 

which focused primarily on biosecurity. 

The following analysis identifies biosecurity-related 

risk factors for E. coli peritonitis relating to farm 

surroundings, farm/house characteristics, human traffic, 

birds and other animals on the farm, and bird/egg 

movement and transport. For the risk factor analysis, 

farms with E. coli peritonitis in the last completed flock 

were compared with farms with no E. coli peritonitis 

problem in the last completed flock. Each factor was 

evaluated individually and adjusted for farm type 

(primary breeder vs. multiplier); factors with a p-value 

≤0.1 were further evaluated in a multivariable logistic 

regression model via a backward elimination process 

(see table below). Results are presented as odds ratios. 

The odds ratio is the likelihood (odds) of a farm having 

E. coli peritonitis in the last completed flock for farms 

with the factor compared with farms without the factor. 

Model-predicted percentage of breeder farms with 

E. coli peritonitis in the last completed flock and 

odds ratios, by farm characteristic 

Characteristic 

Modelpredicted 

pct. with 

E. coli

peritonitis 

Odds 

ratio1 P-value1

History of respiratory 

disease in same flock2 

Yes 56.4 9.4 <.001 

No 19.7 referent 

Spiking males introduced 

in last 

12 months 

 

Yes 22.8 3.9 .006 

No 10.7 referent 

Municipal water source for 

birds’ drinking water 

Yes 12.6 .30 .002 

No 24.1 referent 

Spray tires of vehicles 

entering the farm3 

Yes 13.2 .22 <.001 

No 31.8 referent 

Chicken houses have 

anteroom separating 

“outside area” from “inside 

area” 

 

Yes 17.9 .30 .002 

No 33.4 referent 1

Adjusted for farm type (primary breeder vs. multiplier). 

2 Flock had at least a slight problem with one or more of the following diseases: 

Mycoplasma synoviae, Mycoplasma gallisepticum, infectious laryngotracheitis, 

Newcastle disease, infectious bronchitis, infectious coryza, avian influenza. 

3

Includes feed-delivery vehicles, service tech/veterinarian, catch/vaccination crews. 

Farms with a history of respiratory disease in the last 

completed flock had an increased risk of E. coli

peritonitis. E. coli is a common secondary infection of the 

respiratory tract and may spread from there to the 

peritoneal cavity (Barnes, 2008). 

 Introducing spiking males to a flock—primarily a 

practice used by broiler breeders—stimulates breeding 

activity through competition between the young, spiking 

males and established males. Farms that introduced 

spiking males in the 12 months prior to the survey were 

more likely to experience E. coli peritonitis in the last 

completed flock (OR=3.9). This practice may increase 

the stress level of birds in the flock. 

Using a municipal water source for birds’ drinking 

water was associated with a reduced risk of E. coli

peritonitis. Chlorination of municipal water may reduce 

E. coli contamination. 

Biosecurity measures help prevent the introduction 

of disease pathogens that may secondarily predispose 

birds to E. coli peritonitis. Two biosecurity measures 

were negatively associated with E. coli peritonitis: 

1. Providing an anteroom that separates “outside area” 

from “inside area.” 2. Spraying tires of vehicles entering 

the premises. 

Summary 

E. coli peritonitis is a common problem on breeder 

farms. Flock mortality increases with severity of E. coli

peritonitis. Flocks experiencing respiratory disease and 

farms that introduce spiking males have an increased 

risk of disease, while farms that use a municipal water 

source for birds’ drinking water have a reduced risk of 

disease. Biosecurity measures are important for 

preventing the introduction of disease pathogens, which 

may lead to secondary E. coli infections. Management of 

the poultry-house environment (e.g., temperature, 

lighting, ventilation, etc.) is also important for preventing 

E. coli peritonitis but was not addressed by this study. 

References 

–Barnes J. 2008. Diseases of Poultry, 12th ed. Blackwell Publ., Ames, IA. 706–

707. 

–Beckman B. 2006. Current perspectives on peritonitis. Available at: 

http://www.zootecnicainternational.com/article-archive/veterinary/909-currentperspectives-on-peritonitis.html. Accessed July 16, 2012. 

–Kahn C, ed. 2010. Egg peritonitis. In: Merck Veterinary Manual 10th ed. p 2493. 

For more information, contact: 

USDA–APHIS–VS–CEAH–NAHMS 

NRRC Building B, M.S. 2E7 

2150 Centre Avenue 

Fort Collins, CO 80526-8117 

970.494.7000 

http://nahms.aphis.usda.gov

#660.1012 

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