PATHOLOGY - Backyard Poultry Flocks Flashcards
Which history questions should you ask when investigating backyard poultry flocks?
- Age, breed and sex of the birds?
- What diet are they fed on?
- What has their water intake been like?
- Has there been any diarrhoea?
- Has there been any sneezing?
- What has their mobility been like?
- What is the state of their plumage?
- Have they been treated with anthelmintics recently and if so which product?
- Have they been treated for ectoparasites?
- What are the clinical signs?
- When did you first notice these clinical signs?
- Has the flock been vaccinated? If so for what and when?
- Are any other birds also experiencing clinical signs?
- Have new birds recently been added to the flock? Were they quarantined?
- Are the affected birds in lay?
What is the ideal nutrition for backyard chicken flocks?
Feed a balanced good quality commercial ration sutiable for the age and purpose of the flock and provide soluble and insolube grit to improve egg shell quality and assisit in digestion. Provide clean fresh water daily
What is a commomn nutritional problem seen in backyard flocks?
Obesity
What are the potential consequences of obesity in chickens?
Hens stop laying
Infertility in males
Increase risk of prolapse
What causes egg eating behaviours in chickens ?
Egg eating behaviours develop when a chicken accidentally breaks an egg and thus gets a food reward, causing them to develop egg eating habits
Why are egg eating behaviours more common in backyard flocks?
Egg eating behaviours are more common in backyard flocks as eggs are often left in the nest boxes for longer periods of time
How can you manage egg eating behaviours in backyard flocks?
Provide plenty of nest boxes in a dark area of the shed and raise the boxes above eye level so the chickens are less likely to see and eat the eggs. You can also place fake eggs or ping pong ball in the nests so the chickens will become discouraged from eating the eggs when they get no food reward after pecking
What are the risk factors for feather pecking?
Overcrowding
Stress
Excessive light
Boredom
Nutritional deficiences
Ectoparasites
Concurrent disease
Often caused by a combination of these factors
How can you manage feather pecking in backyard flocks?
Identify and correct the risk factors
Anti-pecking spray
What is the blind/internal layer?
The blind/internal layer is where there are malfunctioning oviducts which do not collect the yolks from the ovaries, resulting the yolk accumulating in the abdomen
What can cause the blind/internal layer?
Stress
Coming into lay
Infectious bronchitis
How can infectious bronchitis cause the blind/internal layer?
Infectious bronchitis early in life can cause permanent damage to the oviducts
Why are blind/internal layers more commonly seen in backyard flocks?
Blind/internal layers are more commonly seen in backyard flocks as backyard flocks don’t tend to be vaccinated against infectious bronchitis and thus are more prone to infection and permanent oviduct damage
What is a key clinical sign of blind/internal layers?
Upright (penguin-like) stance
Abdominal distension
How can you treat blind/internal layers?
Ovariectomy and lavage the abdomen
What is the prognosis for blind/internal layers?
Very poor prognosis, often have to be euthanised
What is egg peritonitis?
Egg peritonitis where yolk materal in body cavity becomes infected with bacteria. This often occurs secondary to blind/internal laying
What are the clinical signs of egg peritonitis?
Dull
Pyrexia
Upright (penguin-like) stance
Abdominal distension
How can you diagnose egg peritonitis?
Clinical signs
Abdominocentesis
How can you treat egg peritonitis?
Fluid therapy
Systemic antibiotics
Ovariectomy and abdominal lavage
What is the prognosis for egg peritonitis?
Very poor prognosis, often require euthanasia
What is ‘the egg bound hen’?
The ‘egg bound hen’ is where a hen is unable to pass an egg that is stuck in the oviduct
What are the risk factors for egg bound hens?
Obesity
Large eggs
Vent trauma
Calcium imbalances
Stress
What are the clinical signs of egg bound hens?
Dull
Straining
Pyrexia (if there is secondary infection)
How can you diagnose egg bound hens?
Clinical signs
Digital probing of the vent
Radiography
How can you treat egg bound hens?
Lubricate the vent and leave the hen in a quiet, dark room
Oxytocin and calcium injections
Antibiotics and NSAIDs (if secondary infection)
Surgery
What is an impacted crop?
An impacted crop is where the crop becomes filled with feed and/or foreign body material and will not empty
What can cause an impacted crop?
Crop foreign body
Marek’s disease
What are the clinical signs of an impacted crop?
Dull
Inappetent
Distended crop
How can you diagnose an impacted crop?
Clinical signs
Palpate the crop
How can you treat an impacted crop?
Surgery and crop lavage
What is the prognosis for crop impaction?
If the crop impaction is caused by a foreign body, the response to treatment and prognosis is good, however if it is cause by Mareks disease, the prognosis is poor
What is sour crop?
Sour crop is where there is a disturbance in the normal flora in the crop resulting in an overgrowth of candida (yeast)
What are the risk factors for sour crop?
Poor nutrition
Mouldy feed
Antibiotic treatment
What are the clinical signs of sour crop?
Dull
Inappetent
Distended, fluid filled crop
How can you diagnose sour crop?
Clinical signs
Palpate the crop
How can you treat sour crop?
Surgery and crop lavage
Antifungal drugs
Probiotics
What is bumblefoot?
Bumblefoot is abscessation of the foot as a result of staphylococcus aureus which enters the foot following abrasion
How can you treat bumblefoot?
Lance and flush the abscesses
Systemic antibiotics
How can you prevent bumblefoot in backyard flocks?
Remove sharp shavings from bedding
Ensure perches are at the correct height
Ensure perches don’t have any sharp edges
Why is it important to ensure perches are at the correct height to prevent bumblefoot?
Ensuring perches are at the correct height is important as high perches can result in foot impact injuries
What is Mareks disease?
Mareks disease is characterised by diffuse T-cell lymphoma usually of the liver, spleen and nervous system, caused by Galid alphaherpes virus infection. This virus is very widespread however specific factors increase the risk of developing clinical signs
Which factors determine if chickens will develop clinical signs of Mareks disease?
Degree of viral challenge
Virus strain
Age of chicken at infection
Genetic resistance of the chicken
Environmental management
Vaccination status
Why is Mareks disease more common in backyard flocks?
Mareks disease is more common in backyard flocks as backyard flocks don’t tend to be vaccinated
What is the typical signalement for Mareks disease?
Mareks disease is only seen in chickens over 8 weeks old
What are the clinical signs of the acute form of Mareks disease?
Clinical signs associated with neoplasia of the liver and spleen
Dull
Poor growth
Diarrhoea
What are the clinical signs for the classical form of Mareks disease?
Ataxia
Paralysis of legs and wings
How can you diagnose Mareks disease?
Clinical signs
Post mortem
Histopathology
How do you treat Mareks disease?
There is no treatment for Mareks disease
What is the prognosis for Mareks disease?
Very poor prognosis
How can you prevent Mareks disease?
Environmental management
Vaccination
Where are red poultry mites typically found in poultry housing?
Red poultry mites are typically found in dark areas of the poultry house during the day, and then at night they will come and feed on the birds
What are the clinical signs of red poultry mite?
Irritation
Stress
Anaemia
Describe the northern mite
The northern mite is a dark brown mite which lives on the birds body, resulting in irritation, particularly around the head. Birds will scratch and appear dull
Describe the common chicken louse
The common chicken louse is a grey/yellow louse usully found under the wings and around the vent. These lice feed off of skin and feather debris resulting in stress and irritation
What is the scaly leg mite?
The scaly leg mite is a microscopic mite which burrows beneath the leg scales resulting in white crusting, raised leg scales, swelling and exudation
What is the typical signalement for the scaly leg mite?
Older chickens
How can you treat the scaly leg mite?
Wash the legs and apply vaseline
What can be used to treat ectoparasites in backyard flocks?
Diamatacious earth
Pyrethroid based spray on products
Exzolt
Ivermectin
What is diatomaceous earth?
Diatomaceous earth can be used to dehydrate and abrasively destroy ectoparasites in the environment
How is exzolt used?
Exzolt is a product that can be put into the drinking water and kills ectoparasites on the host. However, this product is expensive and only appropriate for large flocks
When is ivermectin treatment indicated in backyard flocks?
Ivermectin is indicated if other treatment is unsuccessful. Be aware eggs from the birds treated with ivermectin cannot be used for human consumption
How should you approach investigating diarrhoea in backyard poultry?
- History
- Clinical examination
- Faecal egg and oocyst count
- If negative for eggs and oocysts, consider dysbacteriosis
Which history questions are particularly beneficial when investigating diarrhoea in poultry?
- How old are the birds?
- When was the flock treated with anthelmintics? If so which product was used?
- Are other birds in the flock exhibiting clinical signs?
- What do the faeces look like?
- Is there blood in the faeces?
What are the differential diagnoses for diarrhoea in poultry?
Coccidiosis
Dysbacteriosis
Gastrointestinal helminths
Renal disease
Hepatic disease
What is the typical signalement for coccidiosis in poultry?
Coccidiosis generally only affects birds between 2 to 8 weeks old, or rescue ex-caged hens that have not been exposed to coccidia to develop immunity
How do you treat coccidiosis in poultry?
Anti-coccidial drug
Antibiotics (if secondary bacterial infection)
What is dysbacteriosis?
Dysbacteriosis is a disturbance in the gastrointestinal microbiome, often secondary to intestinal damage due to coccidiosis or intestinal helminths in poultry
How do you treat dysbacteriosis in poultry?
Antibiotics
Probiotics
How do you diagnose gastrointestinal helminths in poultry?
Faecal egg counts
How do you treat gastrointestinal helminths in poultry?
Flubendazole
Fenbendazole
There is no egg withdrawal period for these drugs
How should you approach investigating sneezing in poultry?
- History
- Clinical examination
- Serology and/or PCR
- Treat all birds as a flock and isolate affected individuals
Which history questions are particularly beneficial when investigating sneezing in poultry?
- Are the eggs pale or misshapen?
- Has there been a decrease in egg yield?
- Are other birds in the flock exhibiting clinical signs?
- Have new birds been recently introduced to the flock? Were they quarantined?
- Is there concurrent diarrhoea?
- Has the flock be vaccinated? If so for what and when?
What are the differential diagnoses for sneezing in poultry?
Infectious bronchitis (IB)
Mycoplasma gallisepticum (MG)
Avian metapneumovirus (aMPV)
Infectious laryngotracheitis (ILT)
Syngamus trachea (gape worm)
Newcastle disease (ND)
Avian influenza (AI)
What is the typical signalement for syngamus trachea (gape worm) in backyard flocks?
Syngamus trachea (gape worm) is typically seen in rescue ex-caged hens that have not been exposed to parasite burdens to develop immunity
How is syngamus trachea (gape worm) transmitted?
Syngamus trachea is transmitted through direct ingestion of infective eggs or through ingestion of invertebrate hosts such as snails, slugs and earthworms
What are the clinical signs of syngamus trachea (gape worm)?
Respiratory distress
Stretching the neck
Death
How can you diagnose syngamus trachea (gape worm)?
Faecal egg count
Post mortem (PM)
How can you treat syngamus trachea (gape worm)?
Flubendazole
Fenbendazole
No egg withdrawal period for these drugs
Which of the differentials for sneezing in poultry are notifiable diseases?
Avian influenza (AI)
Newcastle disease (ND)
Which strains of avian influenza (AI) are notifiable?
H5
H7
H5 and H7 and Highly Pathogenic Avian Influenza (HPAI)
What are the clinical signs of highly pathogenic avian influenza (HPAI)?
Dull
Coughing
Sneezing
Nasal discharge
Ocular discharge
Enteritis
Congestion
Sudden drop in feed and water consumption
Sudden drop in egg yield
Rapidly developing high mortality
What are the clinical signs of low pathogenic avian influenza (LPAI)?
Coughing
Sneezing
Nasal discharge
Ocular discharge
Possible drop in feed and water consumption
Possible drop in egg yield
Low mortality
What are the control strategies for avian influenza in the UK?
In the UK, all birds in the affected flock legally have to be culled. Clients will be compensated for losses. A 3km control zone is established around the site, followed by a 10km surveillance zone
What is Newcastle disease?
Newcastle disease is infection of poultry by an avian paramyxovirus serotype 1 (APMV-1) which an intracerebral pathogenicity index (ICPI) of over 0.7 in day old chicks
What are the forms of Newcastle disease?
Viscerotrophic velogenic Newcastle disease
Neurotrophic velogenic Newcastle disease
Mesogenic Newcastle disease
Lentogenic Newcastle disease
What are the clinical signs of viscerotrophic velogenic Newcastle disease?
Gastrointestinal haemorrhage
High mortality
What are the clinical signs of neurotrophic Newcastle disease?
Respiratory clinical signs
Neurological clinical signs
High mortality
What are the clinical signs of mesogenic Newcastle disease?
Respiratory clinical signs
± Neurological clinical signs
Low mortality
What are the clinical signs of lentogenic Newcastle disease?
Mild respiratory clinical signs
What are the sources of infection for Newcastle disease?
Wild birds
Contact with infected poultry
Fomites
Air-borne
Insect-borne
How can you prevent Newcastle disease?
Vaccination
What are the most common causes of chick mortality?
Yolk sac infection
Starve outs
Septicaemia
Aspergilloisis
What are the risk factors for yolk sac infections?
Poor incubation
Dirty eggs in the incubator
Poor hatchery hygiene
Poor brooding hygiene
Stressful brooding environment
What is the typical signalement for yolk sac infections?
Young chicks (usually less than 5 days old)
What are the clinical signs of yolk sac infection?
Small, dull, hunched and inactive chicks
How do you diagnose yolk sac infections?
Signalement and clinical signs
Post mortem (PM)
What are the key signs of a yolk sac infection on post mortem (PM)?
Inflamed yolk sac with foul smelling contents
Fevered carcass
Inflamed umbilicus
Inflamed liver
Inflamed spleen
What is the prognosis for yolk sac infections?
Very poor prognosis and chicks should be euthanised
What is the typical signalement for starve outs?
Starve outs are typically seen in chicks towards the end of their first week of life when the yolk sac begins to run out
What are the clinical signs of a starve out?
Small, dull, hunched and inactive chicks
Empty crop
How do you diagnose starve outs?
Signalement and clinical signs
Post mortem (PM)
What are keys signs of a starve out on post mortem (PM)?
Dehydrated carcass
Dark muscle
Urate in the ureters
Hepatic lipidosis
Enlarged gallbladders
How can you prevent starve outs?
Ensure fresh food and water is readily available
Correct brooding conditions
What is the ideal temperature for a brooding room?
A brooding room should be between 32 - 35°C which will slowly be decreased over 6 weeks until the chicks have feathered and can thermoregulate by themselves
Which pathogens typically causes septocaemia in chicks?
E. coli
Pseudomonas
What is the prognosis for yolk sac infections?
Very poor prognosis and chicks should be euthanised
What is a risk factors for aspergillosis in chicks?
Damp bedding is a risk factor for aspergillosis in chicks
