Question 1

What is Newcastle Disease (ND) in chickens?

Accepted Answer

Newcastle disease (ND), called Ranikhet disease in India, is a highly contagious viral disease of chickens and other birds. Virulent strains can kill most of an unvaccinated flock within days, and milder forms cut growth and egg production. Regular vaccination with live (LaSota, B1, R2B) and inactivated vaccines is the main protection.

Question 2

What is Infectious Bursal Disease (IBD / Gumboro) in chickens?

Accepted Answer

Infectious bursal disease (IBD), commonly called Gumboro, is a viral disease of young chickens that destroys the bursa of Fabricius, the organ that builds immunity. It causes sudden deaths around 3–6 weeks of age and leaves survivors with weakened immunity, so other vaccines work poorly. Vaccine timing must match the chicks' maternal antibody levels.

Question 3

What is Marek's Disease in chickens?

Accepted Answer

Marek's disease is a herpesvirus disease of chickens that causes paralysis, tumours and immune suppression. The virus spreads in feather dust and survives for months in sheds, so almost every flock is exposed. It cannot be treated; protection comes from vaccinating chicks at the hatchery on day one (or in ovo) with HVT, Rispens (CVI 988) or bivalent vaccines.

Question 4

What is Infectious Bronchitis (IB) in chickens?

Accepted Answer

Infectious bronchitis (IB) is a fast-spreading coronavirus disease of chickens. It causes respiratory illness in young birds, kidney damage with some strains, and lasting drops in egg production and shell quality in layers. Because IB exists in many variants, programmes often combine Massachusetts-type (H120, Ma5) and variant (4/91) vaccines.

Question 5

What is Avian Influenza H9N2 (LPAI) in chickens?

Accepted Answer

Avian influenza (bird flu) is caused by influenza A viruses. Low-pathogenic H9N2 causes respiratory disease and production losses, and vaccination against it is permitted in India under DAHD policy using approved inactivated H9N2 vaccines. Highly pathogenic avian influenza (H5N1) is a notifiable disease controlled by the government through detection and culling; preventive H5 vaccination is not permitted in India.

Question 6

What is Fowl Pox in chickens?

Accepted Answer

Fowl pox is a slow-spreading viral disease of chickens caused by an avipoxvirus, carried by mosquitoes and by contact. The dry form causes scabs on the comb, wattles and face; the wet form causes yellow lesions in the mouth and windpipe that can suffocate birds. A single wing-web vaccination gives long-lasting protection.

Question 7

What is Infectious Coryza in chickens?

Accepted Answer

Infectious coryza is a bacterial respiratory disease of chickens caused by Avibacterium paragallinarum. It spreads quickly through a flock, causing swollen faces, foul-smelling nasal discharge and sharp drops in egg production. Recovered birds can remain carriers, so inactivated vaccines covering serotypes A, B and C are used in layers and breeders.

Question 8

What is Mycoplasma (MG / MS) in chickens?

Accepted Answer

Mycoplasma gallisepticum (MG) causes chronic respiratory disease (CRD) in chickens, often made worse by E. coli; Mycoplasma synoviae (MS) causes joint swelling and eggshell problems. Both spread through the egg from infected breeders and between birds. Control relies on MG/MS-free chicks, biosecurity and, where needed, live or inactivated vaccines.

Question 9

What is Egg Drop Syndrome (EDS-76) in chickens?

Accepted Answer

Egg drop syndrome (EDS-76) is caused by an adenovirus that infects the shell gland of laying hens. Apparently healthy birds suddenly lay fewer eggs, with thin, soft, shell-less or pale eggs. Ducks and contaminated water can carry the virus, and it can pass through eggs. An inactivated vaccine given before lay is the standard protection.

Question 10

What is Salmonella in chickens?

Accepted Answer

Salmonella bacteria affect poultry in two ways: host-adapted types cause fowl typhoid and pullorum disease, while Salmonella Enteritidis and Typhimurium often infect birds silently and are a food-safety risk through eggs and meat. Vaccination of layers and breeders, combined with clean feed, rodent control and hygiene, reduces infection and shedding.

Question 11

What is E. coli (Colibacillosis) in chickens?

Accepted Answer

Colibacillosis is infection with harmful strains of E. coli. It is one of the biggest causes of mortality and condemnations in poultry, usually following stress, poor air or water quality, or other infections such as IB, MG and ND. Vaccination plus good hygiene, ventilation and water quality reduce losses.

Disease	Key signs	Birds at risk	Vaccines
Newcastle Disease (ND) Ranikhet disease, ND	Gasping, coughing and nasal discharge; Greenish, watery droppings; Twisted neck, circling or paralysis	All ages of chickens, plus many other bird species. Broilers, layers, breeders and backyard birds all need protection.	Live – eye drop, Live – drinking water, Live – spray, Inactivated – injection, Combination vaccines
Infectious Bursal Disease (IBD / Gumboro) Infectious bursal disease, Gumboro	Depressed birds with ruffled feathers; Whitish, watery droppings and soiled vents; Vent pecking	Chickens mainly between 3 and 6 weeks of age; earlier infection causes silent immunosuppression.	Intermediate, Intermediate plus, Hot strains for severe challenge, Inactivated
Marek's Disease Marek's, MD, fowl paralysis	Paralysis of legs or wings — classic 'one leg forward, one leg back' posture; Grey, irregular pupil ('grey eye') and blindness; Weight loss and pale birds	Chickens of all types; signs usually appear from 6 weeks to several months of age. Long-living layers and breeders are most at risk.	HVT (Herpesvirus of Turkey), Rispens (CVI 988), Bivalent
Infectious Bronchitis (IB) IB, avian infectious bronchitis	Gasping, coughing, rattling breath and nasal discharge; Wet litter and kidney damage with nephropathogenic strains; Drop in egg production	All ages; young chicks suffer respiratory disease and permanent oviduct damage, layers lose production.	Massachusetts (H120, Ma5), 4/91 variant, Inactivated multi-strain
Avian Influenza H9N2 (LPAI) Bird flu, LPAI H9N2	Respiratory signs: coughing, sneezing, swollen sinuses (H9N2); Drop in feed intake and egg production; Higher mortality when combined with other infections	Commercial layers, breeders and broilers, especially in areas with H9N2 circulation.	H9N2 (low-pathogenic) strain, Inactivated, oil-adjuvanted, As per DAHD vaccination policy
Fowl Pox Chicken pox of poultry, avian pox	Wart-like scabs on comb, wattles, eyelids and face (dry pox); Yellow, cheesy patches in mouth and throat; difficulty breathing (wet pox); Reduced feed intake and egg production	Growing birds, layers and breeders; most common in mosquito seasons.	Long-lasting immunity, Simple administration, Suitable for all poultry types
Infectious Coryza Coryza, swollen head in chickens	Swelling of the face and around the eyes; Thick, foul-smelling nasal discharge; Sneezing and watery eyes	Growing pullets, layers and breeders, especially on multi-age farms.	Serotypes A, B, C, Reduces clinical signs, Supports egg production, Oil-adjuvant formulation
Mycoplasma (MG / MS) CRD, chronic respiratory disease, MG, MS	Coughing, rattling breath, nasal discharge (MG); Swollen sinuses and foamy eyes; Swollen hocks and footpads, lameness (MS)	Broilers, layers and breeders; long-living layers on multi-age farms are most exposed.	Live attenuated MG, Inactivated MG, MS vaccines, Combinations
Egg Drop Syndrome (EDS-76) EDS, EDS-76	Sudden drop in egg production in healthy-looking birds; Thin-shelled, soft-shelled or shell-less eggs; Loss of brown shell colour	Layers and breeders at or near the start of lay.	Maintains production, Better shell quality, Reduces economic loss
Salmonella Salmonellosis, SE, ST	Often no visible signs in adult birds (SE/ST); Chick mortality, white pasty vents and poor growth; Diarrhoea, depression and drop in production in outbreaks	Layers and breeders (food safety and egg transmission); young chicks are most vulnerable to disease.	Live attenuated, Inactivated, Multiple serotypes, Reduces shedding
E. coli (Colibacillosis) Colibacillosis, E. coli infection	Yolk sac infection and early chick mortality; Airsacculitis, perihepatitis and pericarditis (fibrin on organs); Lameness, swollen joints, cellulitis	Chicks in the first week, growing broilers and laying hens.	Lower mortality, Better weight gain & FCR, Maternal antibody transfer

Common chicken diseases and their vaccines

Disease-by-disease guides

Newcastle Disease (ND)

Infectious Bursal Disease (IBD / Gumboro)

Marek's Disease

Infectious Bronchitis (IB)

Avian Influenza H9N2 (LPAI)

Fowl Pox

Infectious Coryza

Mycoplasma (MG / MS)

Egg Drop Syndrome (EDS-76)

Combination Vaccines

Salmonella

E. coli (Colibacillosis)

Need help choosing the right vaccines?