Dead squabs/ Dead in shells/ Reduced hatchability/ infertility

PARAMYXOVIRUS

This is a notifiable disease (meaning it must be reported to the APHA).

It is a variant strain of the PMV-1, Newcastle disease (NDv) virus, which is also a notifiable disease. It has been known to spread from pigeons to domestic poultry and gamebird flocks where it causes the NDv syndrome. It targets the kidney and nervous systems.

Symptoms

It can take anywhere from five days to six weeks before birds start to show symptoms after initial infection.

• Diarrhoea/green faeces.
• Loss of balance, leg/wing paralysis, circling.
• Inability to pick up feed.
• Twisted neck (torticollis).
• Medium-high mortality, especially in younger birds.
• Reduced fertility.
• Recovery if showing mild signs takes three to eight weeks.

Diagnostics

Serum antibody levels from live birds to check for exposure if birds aren’t vaccinated.
Viral isolation from tissues taken from birds at post-mortem.
However, these can sometimes not give a definite result.

Treatment

Notify APHA of outbreak (through vet), birds will have to be quarantined for at least two months.
Support birds through the outbreak: electrolytes in water, assisted feeding to prevent starvation for the birds who can’t eat.
Cull severely affected birds on welfare grounds.
Clean and disinfectant all surfaces.

Prevention

Vaccination is required in all UK races. Some outbreaks can still occur despite vaccination.
First vaccine at three to four weeks old.
Adults should be vaccinated each year afterwards before the start of the breeding, showing and racing season.
Injected by sub-cutaneous method at the base of the neck, ensure to clean the needle between birds.
Follow advice on label of the vaccine, most vaccines will deteriorate within one day of being open despite being kept in the fridge rendering them useless.
Colombovac and Nobilis are licensed pigeon vaccines in the UK.

NON-INFECTIOUS CAUSES

Infectious diseases are not the only reason that a flock may become more infertile or have increased incidences of chick/squab death and ‘dead in shells’.

Husbandry or nutritional deficits can also have a major impact on parent bird or squab health and thus death or infertile eggs:

Lack of calcium or vitamin D:

• Results in thin shells which are more at risk of bacterial infiltration or damage.
• Treat by allowing more access to sunlight and increasing the calcium in the diet.

Other vitamin or nutritional deficiencies:

• Results in birds with poor body condition or weakness. These birds will not be prime candidates for mating.
• This could also result in weak chicks. These will be more at risk of contracting disease or tendon/stifle problems.
• Upgrade the diet and supplement with multivitamins.

Overweight or under exercised birds:

• Birds that are kept too fat or that are not exercised enough do not develop the muscle condition required for achieving successful matings.

Unsuccessful pairing:

• Accidental pairing of two males or two females will not be successful.
• An infertile cock bird will not inseminate eggs.
• Two birds may just not be compatible with each other.

Ovary or oviduct dysfunction:

• May produce deformed eggs, eggs with no yolk or double yolked – only one yolk per egg will result in a viable chick.
• Hen may become ‘egg bound’, this may require veterinary intervention if submerging the hen in warm water and applying lubrication around the egg does not work. Do not break the egg as this will cause extensive damage to the inside of the bird.

Humidity:

• If the humidity is too high during incubation or too low at hatching then the chick will not survive.
• Recommended humidity is around 55-60%. Humidity meters are available online.

Early chick death may be caused by:

• Genetic deformities.
• Severe mite infestation.
• Becoming too cold.
• Cannibalism due to overcrowding or stress.
• Inappropriate nesting materials resulting in splayed legs.

Prevention

Close monitoring of the loft will be required during this sensitive time in order for these problems to be addressed before and during the breeding season.

CHLAMYDIA

This disease is a zoonosis. It can cause fever, headaches, pneumonia, meningitis and sometimes even death in humans.

Take extra precautions when handling birds positive for chlamydia, such as wearing gloves, overalls and facemasks. If you have any concerns about your health please contact your GP.

Symptoms

• Affects all ages of birds but clinical disease is worst in young birds.
• Conjunctivitis: Wet eyes, swollen eyelids and sometimes third eyelid protrusion.
• Nasal discharge.
• Gaping/noisy breathing.
• Poor performance.
• Diarrhoea/green faeces.
• Excessive drinking.
• Reduced fertility.

Diagnostics

PCR on pooled sample of faeces.

Treatment

Five-day course of doxycycline. However course may need to be repeated if symptoms persist.
Routine testing is advised after treatment to identify if infection is still present.

Prevention

Healthy birds can carry and spread the disease. Contact between birds of unknown disease status and your own birds is a risk.
Ensure stress factors are kept to a minimum, the following must be looked at:

• A thorough cleaning and disinfection protocol to reduce disease pressure
• Stocking density: is your loft overcrowded?
• Environment: is your ventilation adequate? As a rule, you shouldn’t have cobwebs forming if you having a good throughput of air. Does the loft smell of ammonia? Is it overly dusty?
• Disease control: ensuring absence of other disease such as trichomonas and paramyxovirus will allow birds immune systems to fight off incoming chlamydia more easily.

SALMONELLA

This disease is zoonotic – this means it can cause disease in people.

Should you experience any vomiting, diarrhoea or abdominal pain please contact your local GP.

Symptoms

There are many different types of salmonella, with the most common in pigeons being Salmonella Typhimurium.

Healthy birds can carry this bacterium and shed it intermittently in their droppings.

Affects all ages of bird.

• Decreased appetite.
• Green diarrhoea.
• Increased loft mortality.
• Weight loss.
• Reduced reproductive performance/increased ‘dead in shells’.
• Swollen joints, lameness, drooped wings and difficulty flying.
• Loss of balance, circling and reluctance to move.
• Increased number of dead in shells.

Diagnostics

Three to five days pooled faecal sample for salmonella culture.
As the bacteria is shed intermittently by the birds then samples are sometimes required to be submitted on multiple weeks.
Cull or dead bird submitted for post-mortem.

Treatment

Treat according to culture and sensitivity.

Prevention

Regular cleaning and disinfection of the whole loft.
Avoid stress in the birds (overcrowding, other disease).
Vaccination is also available, but is unlicensed in pigeons.