Chicken Top 6 Diseases, Symptoms and Their Treatment

  What is disease?  

 Any condition that results in deviation from normal function.

How do diseases occur? 

Diseases occur due to the interaction between 3 main factors: 

     1-Agent      2-Host                                                                                                                   3-Environment 

1-Agent Factors: 

• Infectious Agents  

– Bacteria  

– Viruses  

– Parasites  

–  Fungi  

•  Non-infectious agents   

– Chemical  

– Physical  

– Lack or excess of certain vitamins and minerals  

– Toxins 

2-Host Factors:  

• Breed  

• Age  

• Sex  

• Immune status 

3-Management 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 location 

General 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 – Ammonia 

• Nervous (trembling, paralysis, recumbency, circling)      

• Possible Diseases/Conditions:  

– Marek’s Disease        

– Newcastle Disease 

– Fowl Cholera  

– Encephalomyelitis  

– Encephalomalacia (Vit. E/selenium deficiency) 

– Aspergillosis  

– Botulism  

– Bacterial encephalitis

• 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  

– Injury 

• External Signs  

(skin/eye/leg/Foot lessions)                                                                                                        • Possible Disease/Conditions:  

– Lice 

– Mites 

– Biotin deficiency  

– Pantothenic acid deficiency  

– Riboflavin deficiency 

– Gangrenous dermatitis (Clostridium sp; Staph. aureus)eg/foot lesions)                                

• Possible Disease/Conditions:  

– Coccidiosis  

– Necrotic enteritis 

– Coronaviral enteritis   

– Infectious Bursal Disease   

– Ulcerative enteritis  

– Paratyphoid (Salmonella spp.) 

– Worms – Salt poisoning         

Other Signs of Disease or Health Problems: 

• Stress (overcrowding, vaccination reaction, extreme temperatWhat 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 farmsures, lack of feed or water)  

                   

Not 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)
• Sanitation 

 Use 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 time. 

Common Poultry Diseases:

 

1-Infectious Laryngotracheitis: 

Introduction

A herpesvirus (pathogenicity can vary) infection of chickens, pheasants, peafowl and turkeys with a morbidity of 50-100% and a mortality usually 10-20% but sometimes up to 70%. Recovered and vaccinated birds are long-term carriers. The route of infection is via upper respiratory tract and conjunctiva or possibly oral and the course of the disease is up to 6 weeks. Fairly slow lateral spread occurs in houses. Transmission between farms can occur by airborne particles or fomites.

The virus is highly resistant outside host but is susceptible to disinfectants. Movement and mixing of stock and reaching point of lay are predisposing factors.

Signs

• Dyspnoea.
• Gasping.
• Coughing of mucus and blood.
• Drop in egg production.
• Ocular discharge.
• Sinusitis.
• Nasal discharge (low pathogenicity strains).

Post-mortem lesions

• Severe laryngotracheitis, often with blood in lumen, caseous plugs may be present.
• Microscopically - intranuclear inclusions in tracheal epithelium.

Diagnosis

Signs, lesions, in severe form may be enough. Isolation in CE CAMs, histology, IFA, PCR. Differentiate from Newcastle disease, severe bronchitis. Sera may be examined by VN or Elisa.

Treatment

None, antibiotics to control secondary bacterial infection if this is marked.

Prevention

Quarantine, vaccination, if enzootic or epizootic in an area, after 4 weeks of age. All-in/all-out operation. Keep susceptible stock separate from vaccinated or recovered birds. Apply strict biosecurity in moving equipment or materials between these these categories of stock. 

  

2-Mycoplasmosis (Chronic Respiratory Disease): 

Species Affected  

• Chickens and turkeys  

 Cause  

• Mycoplasma gallisepticum – Secondary E. coli infection is common  
• Transmitted through the egg, airborne droplets, or from bird to bird 

Signs 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 age 

3-Internal Parasites:  

Species Affected 

• All birds  

Cause  

• Roundworms (Ascarids)
• Hairworms (Capillaria)
• Cecal worms (Heterakis)
• Tapeworms (Cestodes) 

Signs and Lesions 

• Unthriftiness, stunted growth, emaciation
• Enteritis
• Anemia
• Decreased egg production  

Prevention 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 hairworms 

4-Coccidiosis: 

  Species Affected  

• Chickens and turkeys

  Cause 

• 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 ceca 

• Intestinal coccidiosis (caused by E. acervulina, E. brunetti, E. maxima, and E. necatrix) 

 – Loss of weight  

 – Shriveled combs  

 – Drop in egg production 

 – Pale shanks 

Prevention and Control 

• Good management
• Provide medicated feed (with coccidiostats such as amprolium or Amprol™)
• Treat infected flocks promptly  

5-External Parasites: 

Species Affected 

• All birds 

Cause 

• Scaly leg mite (Knemidocoptes mutans)  

• Chicken mite (Dermanyssus gallinae)  

• Northern fowl mite (Ornithonyssus sylviarum) 

Signs and Lesions  

• Scaly leg mite: – scales and crusts in legs, combs, and wattles  

• Northern fowl mite: – blackened feathers, scabby skin around vent 

Prevention 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

 6-Bumblefoot (Pododermatitis) 

Species Affected 

• Chickens (mostly males and heavy birds) 

 Cause  

• 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 

Signs and Lesions  

• Lameness
• Swelling of the foot pad
• Hard, pus‐filled abscess on foot pad 

Prevention 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. 

 Author: Kashif Ch