Common Poultry Diseases and

Their Prevention

Dr. Nathaniel L. Tablante

Associate Professor and Extension Poultry Veterinarian

VA-MD Regional College of Veterinary Medicine

University of Maryland College Park

• How diseases occur: basic principles
• Observing your birds for signs of disease
• What to do when disease is suspected
• When to start treatment or intervention
• Common poultry diseases
• Final thoughtsWhat is disease?
• Any condition that results in deviation from

normal functionHow do diseases occur?

Agent

Host Environment

Diseases occur due to the interaction between 3 main factors:

NOTE: Not all poultry health and production problems are caused by infectious agents.

LOOK AT MANAGEMENT FACTORS FIRST BEFORE CONSIDERING INFECTIOUS DISEASEAgent Factors

• Infectious Agents

– Bacteria

– Viruses

– Parasites

– Fungi

• Non-infectious

agents

– Chemical

– Physical

– Lack or excess of

certain vitamins and

minerals

– Toxins

http://health.utah.govHost Factors

• Breed
• Age
• Sex
• Immune statusManagement and Environmental

Factors

• Feed quality
• Lighting program
• Air quality and ventilation
• Water quality
• Space (floor or cage,

feeder, drinker)

• Sanitation
• Vaccination and

medication programs

• Weather
• Season
• Geographic locationGeneral Signs of Disease
• Poor appetite
• Huddling
• Depression
• Runting/stunting; poor

uniformity

• Ruffled feathers
• Coughing, sneezing,

oculo-nasal discharge,

difficult breathing

• Bloody or wet litter
• Increased mortality Specific Signs of Disease
• Respiratory

(gasping, coughing, snicking,

swollen eyes, nasal

discharge)

• Possible

Diseases/Conditions:

– Avian Influenza

– Newcastle Disease

– Infectious

Laryngotracheitis

– Infectious Bronchitis

– Mycoplasmosis

– Colibacillosis

– Fowl Cholera

– AmmoniaSpecific Signs of Disease

• Nervous

(trembling, paralysis,

recumbency, circling)

• Possible

Diseases/Conditions:

– Marek’s Disease

– Newcastle Disease

– Fowl Cholera

– Encephalomyelitis

– Encephalomalacia (Vit.

E/selenium deficiency)

– Aspergillosis

– Botulism

– Bacterial encephalitisSpecific Signs of Disease

• Locomotor

(crooked toes, swollen hocks,

hyper-extended or rubbery

legs)

• Possible

Diseases/Conditions:

– Rickets (Ca/P/Vit. D3

deficiency or imbalance)

– Riboflavin deficiency

– Biotin deficiency

– Synovitis

– InjurySpecific Signs of Disease

• External Signs

(skin/eye/leg/foot lesions)

• Possible

Disease/Conditions:

– Lice

– Mites

– Biotin deficiency

– Pantothenic acid deficiency

– Riboflavin deficiency

– Gangrenous dermatitis

(Clostridium sp; Staph.

aureus)Specific Signs of Disease

• Digestive

(bloody or watery feces)

• Possible

Disease/Conditions:

– Coccidiosis

– Necrotic enteritis

– Coronaviral enteritis

– Infectious Bursal Disease

– Ulcerative enteritis

– Paratyphoid (Salmonella

spp.)

– Worms

– Salt poisoningOther Signs of Disease or Health Problems

• Stress

(overcrowding, vaccination reaction, extreme temperatures, lack

of feed or water)What to do if your birds look sick:

• Isolate sick bird(s) immediately
• Dispose of dead birds promptly

and properly

• Observe the rest of the flock for

signs of disease

• Call veterinarian, animal health

technician, or Extension agent

for advice and assistance

• Do not move birds or eggs off

your farm

• Do not add new birds to flock
• Do not visit other farmsNot all poultry health problems are caused by infectious agents

Always consider non-infectious

conditions (management

factors or FLAWSS) first:

• Feed quality
• Lighting
• Air quality and ventilation
• Water quality
• Space (feeders and drinkers)
• SanitationUse medications judiciously and only when necessary
• Management problems can

only be fixed by proper

management changes and/or

corrections

• Viral infections cannot be

treated with antibiotics

• Bacterial infections can only

be treated with the proper

antibiotic

• Always consult a veterinarian

before initiating any treatment

• If antibiotics or other drugs

are prescribed, follow

recommended dose, route,

duration of therapy, and

withdrawal timeCOMMON POULTRY DISEASESInfectious LaryngotracheitisSpecies Affected

• Chickens, pheasants, peafowl

fishandgame.idaho.gov

scienceblogs.com

nathistoc.bio.uci.eduCause

• Herpes virus
• Spread through infected birds and improperly

administered live vaccines

– Airborne transmission or through contaminated

equipment, shoes, and clothingSigns and Lesions

• Respiratory distress,

coughing, sneezing,

expectoration of

bloody mucus

• Conjunctivitis and

facial swellingPrevention and Control

• Vaccination

– Do not vaccinate if the disease is not present or has not

been observed in your area

– If vaccination is deemed necessary, MDA allows only

Tissue Culture Origin (TCO) ILT vaccine in non-commercial

poultry

• Biosecurity

– Do not allow visitors to your farm nor visit other farms

– Do not share equipment and vehicles

– Clean and disinfect poultry house, coops, and equipment

regularly and between flocksMycoplasmosis

(Chronic Respiratory Disease)Species Affected

• Chickens and turkeys

nrm.wikipedia.org

en.wikipedia.orgCause

• Mycoplasma gallisepticum

– Secondary E. coli infection is common

• Transmitted through the egg, airborne

droplets, or from bird to birdSigns and Lesions

• Coughing, sneezing,

facial swelling, nasal

discharge, cloudy air

sacs

• Deformed eggs, drop in

egg production

• Pericarditis and

perihepatitis (with

secondary E. coli

infection)Prevention and Control

• Purchase chicks only from MG-negative

sources (National Poultry Improvement Plan

or NPIP participant)

• Provide medicated feed (containing Tylan® or

Gallimycin®)

• Don’t mix birds of different species and ageInternal Parasites

www.backyardchickens.comSpecies Affected

• All birdsCause
• Roundworms (Ascarids)
• Hairworms (Capillaria)
• Cecal worms (Heterakis)
• Tapeworms (Cestodes)Signs and Lesions
• Unthriftiness, stunted

growth, emaciation

• Enteritis
• Anemia
• Decreased egg

productionPrevention and Control

• Rotate birds in yards or pens
• Deworm flocks regularly, particularly those raised on the

ground or in floor pens

• Provide medicated feed (containing broad-spectrum

dewormer)

• Treat infected birds with the proper dewormer

– Piperazine (Wazine™) is effective only against roundworms and

cecal worms

– Fenbendazole (SafeGuard™ or Panacur™) is effective against

roundworms, cecal worms, and hairwormsCoccidiosisSpecies Affected

• Chickens and turkeys

tinyfarmblog.comCause

• Eimeria sp.
• 9 species in chickens
• 7 species in turkeys
• Transmitted through infected droppings

(containing oocysts)Clinical Signs and Lesions

• Cecal coccidiosis

(caused mainly by E.

tenella in chickens)

– High mortality

– Bloody feces

– Pale combs

– Ruffled feathers

– Lack of appetite

– Coagulated blood in

cecaClinical Signs and Lesions

• Intestinal coccidiosis

(caused by E. acervulina, E.

brunetti, E. maxima, and E.

necatrix)

– Loss of weight

– Shriveled combs

– Drop in egg production

– Pale shanksPrevention and Control

• Good management
• Provide medicated feed (with coccidiostats

such as amprolium or Amprol™)

• Treat infected flocks promptlyExternal Parasites

www.tillysnest.comMites

keep-hens-raise-chickens.comSpecies Affected

• All birdsCause
• Scaly leg mite (Knemidocoptes mutans)
• Chicken mite (Dermanyssus gallinae)
• Northern fowl mite (Ornithonyssus sylviarum)

www.ca.uky.edu

www.chickenvet.co.ukSigns and Lesions

• Scaly leg mite:

– scales and crusts in

legs, combs, and

wattles

• Northern fowl mite:

– blackened feathers,

scabby skin around

ventPrevention and Control

• Scaly leg mite

– Cull or isolate affected birds

– Apply an oil-based product such as petroleum jelly, a 50:50

kerosene and cooking oil mix, or Blue Ribbon™ (a commercial

mixture of plant oils, canola, and camphor) to affected areas

• Northern fowl mite

– Monitor all birds and facilities for infestation; check egg flats and

cases for mites

– Treat birds with approved insecticide (such as carbaryl or Sevin™)

– Use dry powder to dust birds

– Use liquid spray or wettable powder for walls and floors to penetrate cracks

and crevices

– Wash plastic flats and racks with hot water and detergent

-Always follow the manufacturer’s directions.

-Observe all warnings and withdrawal periods.Bumblefoot

(Pododermatitis)

www.backyardchickens.comSpecies Affected

• Chickens (mostly males and heavy birds)

www.flickr.comCause

• Injury to the lower

surface of the foot and

subsequent infection with

Staphylococcus bacteria

• Common causes of injury:
• Rough perches
• Splinters
• Wire floors
• Poor litter or bedding

quality www.avianweb.comSigns and Lesions

• Lameness
• Swelling of the foot

pad

• Hard, pus-filled

abscess on foot pad

keep-hens-raise-chickens.comPrevention and Control

• Provide good quality litter or bedding. Keep

bedding clean, dry, and deep.

• Keep perches less than 18 inches from the

floor to prevent foot damage due to impact

from jumping.

• Remove potential sources of injury such as

sharp objects and/or surfaces.Treatment

• Soak foot in warm water and Epsom salts.
• Clean affected area with soap and warm water, then

disinfect with alcohol.

• If skin is open, drain pus from abscess (If there is no break

in the skin to allow drainage of abscess, use a sterile scalpel

or sharp end of a disinfected blade to cut a small opening).

• Flush the abscess cavity with hydrogen peroxide to clean

out pus and debris.

• Pack the cavity with antibiotic ointment and wrap the foot

with gauze and elastic bandage. Repeat daily until foot

heals.FINAL THOUGHTS

• Be vigilant – continuous flock health monitoring is a

MUST

• Use all available senses (sight, touch, smell,

hearing) as well as COMMON SENSE

• Look for all possible causes and/or predisposing

factors, i.e. do not “leave any stoned unturned”

• Initiate corrective or preventive measures promptly
• When in doubt, seek expert advice
• While practicing strict biosecurity, provide adequate

feed, water, ventilation, heat, etc. (a.k.a. bird comfort

or TLC)Questions?

http://extension.umd.edu/sites/extension.umd.edu/files/_docs/Common-Poultry-Diseases-and-Their-Prevention_Tablante_2013.pdf