Remember that the respiratory system of a bird includes
lungs, air sacs and hollow bones. Therefore, keep dust and ammonia
levels low which will help the health and welfare of poultry since
ammonia paralyses the small hairs (cilia) which act like an
escalator to move normal mucus up the trachea before being
swallowed. If these are impaired, viruses, bacteria and fungi have
a greater chance of colonising the bird in its air sacs, lungs and
bones and causing disease which is therefore very difficult to
Avian Influenza: (this highly contagious
infectious disease is notifiable.)
Cause and signs
Free-range birds are
considered to have a high risk of infection from wild birds
carrying the virus. There are several viruses that cause concern in
poultry e.g. H7N7 and the potentially zoonotic (transmissable to
humans) H5N1. Influenza viruses may be low pathogenic (LP) or high
pathogenic (HP). It is the latter variant that causes sudden
multiple deaths in bird flocks.
Poultry owners should have
knowledge of what signs to look out for: high, rapid and
unexplained mortality and a severe drop in egg production should
immediately alert the owner to a problem.
- Large numbers of depressed, sick and dying birds
- Panting with open mouth
- Discharge from eyes and nostrils
- Dark congested comb and wattles (the main difference
from Newcastle Disease signs)
- Swelling of the head
- High fever
Differential (other possible/similar)
- Newcastle Disease: nervous signs such as twisted neck,
trembling or difficulty in walking
- Infectious Bronchitis: respiratory noise, discharge from eyes
and nostrils, egg production drops but not significant acute
- Mycoplasma: severe sinusitis, head swelling, sweet sickly
smell, congested nostrils.
Bacterial respiratory pathogens:
Ornithobacter rhinotrachale (ORT)
Haemophilus paragallinarum (fowl coryza)
E. coli as secondary infection
Fig 1: Avian Influenza showing congested comb and
AI is a serious viral disease which is rapidly
fatal. Like other influenzas, there are various strains, some more
dangerous (pathogenic) than others. The most likely route of
introduction to an area is by free-flying waterfowl, but domestic
waterfowl can carry it with few clinical signs and then infect
The virus is mainly transmitted in droppings and can survive in
damp and warm conditions for 40-60 days: a tiny amount can infect
huge numbers of birds. It is easily transported by contaminated
muck on boots, clothing, dirty crates or vehicles (formites). It
is, however, susceptible to approved virucidal disinfectants. A
list of approved disinfectants is on the DEFRA website.
There is no AI vaccine available at present.
Control of an
biosecurity including wild bird exclusion, slaughter and possible
de-population of surrounding area. If pure breed that are not
infected can be housed, they may escape slaughter (see If
an outbreak occurs, below).
Paramyxovirus: Newcastle Disease (ND) or Fowl
This was first isolated in
1926. It is also a notifiable disease. All birds
are susceptible especially chickens and turkeys. Pigeon
paramyxovirus reached the UK in 1983 and has caused outbreaks in
outdoor flocks through contamination of feed. ND is also a serious
viral disease which is rapidly fatal. ND is zoonotic with flu-like
symptoms and conjunctivitis.
Signs are very variable and
may affect the respiratory and nervous systems and may cause a drop
in egg production and soft-shelled eggs, greenish loose faeces,
torticollis (twisted neck) and sudden death. A recovered chicken
may have asymmetrical pupil size for life, something judges of pure
breeds check for since it then disqualifies a bird from
The paramyovirus survives in the dead host for several weeks at
cool temperatures or several years if frozen, and in faeces for
over a month. Birds imported into the UK from outside the EU (if
allowed under current regulations) have to be quarantined for 35
days and 8 week old, unvaccinated chickens are used as sentinels.
The UK is mostly clear of the disease but outbreaks do occur from
time to time (the most recent one via feral pigeons).
Fig 2: Newcastle Disease showing
The main distributors can be pigeons which carry a close variant
of the virus, waterfowl can carry ND with few clinical signs. The
virus is transmitted by aerosol and in droppings. It can survive in
the dead host or in excretions for several weeks at cool
temperatures, several years if frozen. High (over 37°C)
temperatures reduce this to about 30 days. It is easily transported
by contaminated muck on boots, clothing, dirty crates or vehicles
(known as fomites) and by wild birds. It is susceptible to approved
virucidal disinfectants. A list of approved disinfectants is on the
There is an efficient vaccine (no vaccine is 100% effective,
vaccines reduce signs of the disease but may mask the presence of
disease). Only in the face of an outbreak is vaccination
recommended, but racing pigeons are compulsorily vaccinated.
Control of an oubtreak
Vaccination, movement restrictions, biosecurity, some
AVIAN INFLUENZA AND NEWCASTLE DISEASE: WHAT DO WE
NEED TO DO?
In 2003 Holland was ravaged by Avian Influenza (AI). Many shows
were cancelled and many pure breed poultry slaughtered.
Understandably, no-one wishes to go through that again or indeed
for it to happen in this country with our strong tradition of
poultry keeping, breeding and exhibiting. AI is becoming endemic in
Europe and there have been several outbreaks in commercial units in
the UK since 2003.
DEFRA knows the unique genetic position of pure breeds via The
Poultry Club and has advised the Fancy what would be needed if an
outbreak of AI or another serious disease such as ND occurs in the
Some breeders already protect their birds against ND by
vaccination: there is no
Similar protection against AI. However, some simple biosecurity
measures will go a long way towards prevention of a devastating
outbreak of either disease in your flock and in the poultry
industry and Fancy generally.
Biosecurity in a free-range flock
- Keep feed under cover to minimise wild bird attraction.
- Keep water fresh and free of droppings.
- Keep waterfowl and chickens separate.
- Control vermin.
- Quarantine new stock for 2-3 weeks.
- Quarantine birds after taking to an exhibition for 14-21
- Change clothes and wash boots before and after visiting other
- Change clothes and wash boots before and after attending a
- Keep fresh disinfectant at the entrance to poultry areas for
- Disinfect crates before and after use, especially if lent to
others. However, it is preferable not to be sharing equipment.
- Disinfect vehicles which have been on poultry premises but
avoid taking vehicles onto other premises.
- Monitor any disease signs and report any suspicion of
- Comply with any import/export regulations/guidelines.
These are common-sense measures which can easily be incorporated
into daily routine and are designed to protect your
If an outbreak occurs
Laws are already in place for carrying out disease control
measures as speed is of the essence in order to prevent disease
spreading. If either AI or ND is suspected, DEFRA must be informed
immediately and State Veterinary Inspectors will then visit the
suspected premises. Samples will be taken, movement restrictions
will be imposed on the infected premises. If AI or ND is confirmed,
all movements would be stopped (possibly nationally or regionally)
until the disease situation can be assessed. Restrictions will not
be eased until DEFRA is confident it will not increase the risk of
spread of disease. All birds (and eggs) on the infected premises
will be slaughtered (as will birds that risk assessments determine
are certain to catch the disease - Dangerous Contacts).
Compensation would then be paid on birds that were not diseased at
the market value of the birds at the time of slaughter. The source
of the disease would be investigated.
Established pure breed flocks may be exempt from this if there
has been no contact with the affected flock: tracings of movements
will confirm this. It is likely that they will have to be housed. A
surveillance zone of minimum 10 kilometre radius around infected
premises would be maintained for at least 30 days. If a laying
flock is infected, any eggs could only be sold to poultry-free
premises and only for consumption or processing.
If ND is suspected, poultry in the surrounding zones may have to
be vaccinated, other restrictions applying.
Unlike the Fancy, DEFRA works on a flock basis, thus, in order
to consider any sort of pure breed exemption in the unlikely event
that a firebreak cull becomes necessary to stop disease spreading
they would need to know where the flocks are in advance, the GB
Poultry Register is for flocks over 50 birds, but The Poultry Club
has an efficient Ringing Scheme which would help with this.
Other respiratory conditions
Blocked nasal openings: this can obviously be a
problem with chronic respiratory problems. Discharge accumulates
and hardens at the nasal opening but it is possible to soak and
remove this carefully from a conscious bird, remembering that some
species have a sensitive operculum (nostril cover), which needs to
remain in place.
all classes of poultry are susceptible. It is a very difficult
disease to treat successfully as there are few early symptoms and
once it spreads throughout the air sacs, lungs, hollow bones and
abdomen it is probably too late. Mouldy hay or straw or rotting or
decaying vegetable matter, such as bark, should be avoided as a
substrate, as it is the spores of the fungus that are inhaled, wood
chips do not support the fungus. Most healthy unstressed birds will
cope with a low level of infection, but birds under stress may die
suddenly. It is also passed to the chick through the egg. This
disease is zoonotic, causing Farmer's Lung in humans.
Antifungal agents such as itraconazole are successful if the
disease is caught early enough, or the affected bird can be
nebulized with F10, a disinfectant which is non-toxic to the
Fig 3: Aspergillusin the air sac (grey
patches, yellow arrow)
Air sacculitis: this is a general term covering
several air sac diseases in all poultry ranging from parasitic (air
sac mites: mainly a problem in very small adult birds) to
chlamydiosis to aspergillosis.
Air sac leakage: subcutaneous emphysema
sometimes occurs, usually the cervical air sac leaks and air
appears under the skin locally or all over, making the bird look
like a balloon caricature. If this does not resolve in a few days,
a nick can be made in the skin to let the air out. This small
amount of skin can then be sutured open which aids the air sac to
heal by slow metabolism.
Infectious Bronchitis (IB): this is a
coronavirus causing respiratory disease and kidney damage in young
poultry, plus oviduct infection with depressed egg production and
poor shell quality (often wrinkled) in layers as the shell gland is
affected. Birds laying the odd wrinkled egg may be carriers and
should be culled. Poor shaped eggs should not be set for hatching.
The signs of IB are similar to mycoplasma and the spread of
infection is 1-3 days throughout a flock: mycoplasma tends to have
lower morbidity (affected birds). Commercial flocks vaccinate
against IB and ND with a combined vaccine and pet bird owners may
opt to do the same if there is a problem in the area. However,
vaccination has not proved to give particularly good control in
outdoor birds. Because the presence of mycoplasma predisposes
birds to IB, it is very important to control the incidence of
mycoplasma in the flock (see Mycoplasma Bulletin).
Figs 4 and 5 Mis-shapen eggs and wrinkled shells caused by
Pasteurella multocida: a commensal
(normal inhabitant) in many mammals but not generally in poultry or
wild birds. Rats are a known infective source. The disease is known
as fowl cholera and symptoms include respiratory distress,
lameness, lethargy and swollen wattles. Antibiotics and
sulphonamides are effective and there is also a vaccine.
Chlamydiosis: Chlamydia psittaci,
known as psittacosis in parrots or ornithosis in other birds, this
is a potentially dangerous zoonotic disease as it may cause
pneumonia and abortion in humans. Bird keepers need to inform
their doctors of their hobby so that in event of illness this
disease may be part of the differential diagnosis. Infection
in birds can cause ocular and nasal discharge and distressed
breathing. It is confirmed by laboratory (ELISA) test. There
is a misconception that it can only be caught from parrots, but
turkeys, ducks, pigeons and sheep have also been implicated. It is
a difficult organism to treat as it has as part of its life cycle a
stage that hides inside cells, therefore long term antibacterials
have to be used.
Infectious Laryngotracheitis (ILT): this is
caused by a herpesvirus and mainly affects male, heavy breed
chickens and turkeys. Symptoms are a nasal discharge, gasping and
tracheal plugs of mucus which can cause death. Mycoplasma, IB,
Vitamin A deficiency and ammonia will predispose to more severe
disease plus there is a carrier state. There is a vaccine.
Fig 6: Bloody mucus in trachea:
Infectious Laryngotracheitis (ILT)
Economic impact of any respiratory problem
A notifiable disease outbreak
can cause loss of entire flocks whether through death or culling
and any compensation is based on commercial values - pure breeds
are only valued as if they were commercial layers or meat
Lesser respiratory problems
can at least cause loss of production plus poor welfare for the
It is a fact of life that
cockerels will crow! There is no method of physically silencing
them, but putting them in a dark box of suitable dimensions
overnight to reduce the sound and frequency will often placate
unhappy neighbours. It is illegal to surgically de-voice cockerels
or peacocks in the UK.
Those who wish to breed chickens must take in to account the
fact that an average of 50% of the hatch will be males and decide
what to do with them. There is little or no market for spare
cockerels, but they can of course make a tasty meal.