The Chicken Vet Talks About Respiratory Disease In Chickens

One of the most common veterinary complaints of backyard chickens is snicking, sneezing and coughing.

Respiratory disease often presents itself with one or more birds sneezing / snicking. These birds can have a runny nose and foamy running eyes. In severe cases these birds can have swollen sinuses (presents as swelling around the eyes), stop eating and in extreme cases die.

There a number predisposing factors for respiratory disease in chickens: as with any animal stress can cause an underlying disease to show itself. This stress could be extremes of temperature and humidity, high stocking density, being transported, being taken to a poultry show and new animals being introduced to an existing/established flock.



Gapeworms (Syngamus trachea) are included under 'respiratory system' since the adult worms reside in the trachea (or windpipe) and often produce a gurgling or 'tracheal rattle' that can be confused with respiratory problems.

Gaping-chickenGapeworm is common in pheasants but also affects chickens, guinea fowl and turkeys. Gapeworms can cause considerable losses in pheasants and turkeys. Gasping for breath or 'gaping' as it is known is the biggest sign of gape worm. Shaking of the head and neck stretching are also common. When birds are held, gurgling can often be heard. If a heavy infestation occurs, death by suffocation will occur. Fully grown gape worms are 'Y' shaped and vary in size between 1 and 2cm long.They are blood red in colour (as can be seen in the second photo during a post mortem).


Mycoplasma Gallisepticum

Many backyard flocks these days are carrying Mycoplasma. There are many different kinds of Mycoplasma but Mycoplasma Gallisepticum (M.G) is the most common. 

Mycoplasma Gallisepticum causes respiratory disease and can weaken the birds immune system sufficiently for them to pick up any disease that they come into contact with. Small bubbles in the corners of eyes and swollen sinuses are usually the first sign of Mycoplasma. Once birds have been infected, they become carriers and remain infectious for life. Some birds seem to have a good resistance to M.G. and out of an infected flock, a few may die, others may become ill and recover and some may not show any symptoms at all. The first time they are ill seems to be the worst and subsequent outbreaks seem to be milder.


Infectious LaryngioTracheitis (ILT)

When we think of respiratory disease in poultry we often think of infectious bronchitis virus or Mycoplasma, however there is another rather harmful virus that belongs to the herpes virus family that causes ILT.

The virus is spread though birds inhaling or ingesting the virus. It goes on to replicate in the trachea (the windpipe) of the chicken leading to inflammation of the trachea. This causes the bird to gasp for air often resembling gape worm infection. In very severe cases the inflammation is so severe that the bird bleeds into its trachea. This blood goes on to clot and can block the windpipe suffocating the affected bird.


The Chicken Vet Talks About Newcastle Disease

Newcastle disease was first found in Newcastle-upon-Tyne in 1926.The disease is caused by a virus called Avian Paramyxovirus Type 1.

Whilst we tend to think of Newcastle disease as being associated with large numbers of dead birds it is important to remember that the disease varies from lentogenic (moderately pathogenic) strains which cause mild respiratory disease and low mortality through to velogenic (highly pathogenic) strains which are associated with high mortality.

The velogenic strains cause high mortality (up to 100%) and spread rapidly causing respiratory and nervous signs. These strains can be subdivided further:


Chlamydiosis In Poultry

There is a misconception that Chlamydia can only be caught by humans from parrots, but it is common in pigeons, occasional in turkeys and ducks and is becoming more common in chickens.

It is known as psittacosis in parrots or ornithosis in other birds, this is a potentially dangerous zoonotic disease as it may cause flu-like symptoms, pneumonia and abortion in humans.


The Chicken Vet Talks About Avian Influenza

The very mention of the words Avian Influenza (AI) or Bird Flu strikes fear into the hearts of poultry keepers and the general public alike.

Avaian-InfluenzaAvian Influenza is caused by an Influenza virus of which there are several strains. Some of these strains infect only people, others only birds and some only pigs. However some strains have the ability to infect more than one species however they usually have a preference for infecting one species. E.g. A strain of Influenza that infects birds may readily spread between poultry but may struggle to infect people and will only do so in rare circumstances. Why human health professionals become concerned about bird flu is that if there ever was a strain that could readily infect both people and birds, it would be a challenge to control.


Infectious Bronchitis

Infectious bronchitis (I.B) is the most contagious poultry disease. It has very similar symptoms to mycoplasma. The main difference is the number of birds it affects.

Mycoplasma tends to affect a few birds in the flock but IB spreads within a few days to the whole flock. I.B. causes respiratory disease and kidney damage in growers and oviduct infection in adult hens which can cause wrinkled egg shells as well as a reduction in egg laying. It can also affect the ability of the bird to produce thick albumen (white). Commercial flocks vaccinate against Newcastle disease and infectious bronchitis at the same time. Survivors of IB are immune but will always be carriers.


Newcastle Disease

Newcastle disease is fairly common around the world but thankfully, the UK doesn't have many outbreaks. The symptoms of Newcastle disease can be quite varied. Newcastle disease is a notifiable disease in the UK.

Commercial flocks are vaccinated against Newcastle disease at the same time as they are vaccinated for infectious bronchitis and all racing pigeons leaving the UK (and returning on their own hopefully!) are vaccinated against it. The virus is quite tough, being able to survive in dead birds for many weeks afterwards.



Aspergillosis is an infectious fungal disease affecting poultry in which birds will usually be left gasping for breath.

The disease is contracted by inhalation when there is a high spore count in the air. Disinfectant has little effect on the spores. The incubation period of the infection is between 2 and 6 days and it can infect plants and many other species of animals.


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