Page 9 - Clinical Connections - Spring 2024

Pathology
WHAT IS WRONG WITH MY BACKYARD
CHICKENS?

Sonja Jeckel, Senior Lecturer in Farm Animal Disease Diagnostics

eeping backyard chickens is
popular in the UK and numbers
K are presumed to have consistently
increased over the last 20 years. However,
precise numbers are unknown as only flocks
with more than 50 animals are obliged to be
registered with the Animal and Plant Health
Agency (AHPA).
Though the general understanding
of diseases in backyard chickens has Figures 2a and 2b: Infectious laryngitis (ILT) in a chicken. The laryngeal opening is blocked by a
increased among vets in general practice large plug of necrotic tissue extending into the trachea
(to fulfil the needs of their clients), specific
disease diagnostics in backyard chickens Investigations of caseous necrotic material blocking
remains challenging due to limited testing Examples of PME investigations done by the laryngeal opening. Histopathology
options and potentially high associated us include confirmation of Marek’s disease, frequently allows for confirmed diagnosis
costs. one of the more common and serious by detecting herpesviral inclusion bodies
Investigating a disease problem in a diseases in backyard chickens. In some of in the tracheal epithelium. The confirmed
backyard chicken may be an indicator these cases, Marek’s disease was clinically diagnosis is significant for the remaining
of a process affecting other birds in the suspected by the submitting vet, as the flock with regards to recommendations on
small flock. Therefore, some owners are chickens presented with neurological clinical vaccinations and new bird introduction.
keen to reach a diagnosis and assess the signs. Confirmation by PME was sought However, not all of our PME cases in
significance of the disease process for the due to the potential significant implications backyard chickens have wider implications
remaining flock, even after the individual for the flock. In other cases, chickens just – and most owners and submitting vets are
bird affected has passed away. presented with progressive loss of condition a lot happier and relieved about diagnoses
In such follow-up investigations, the RVC and the cause of the demise was unclear at like egg peritonitis or adenocarcinoma
Farm Animal Pathology and Diagnostics submission. without any indication for additional
Services (RVC-FAPD) supports vets underlying serious disease. Even in some of
in practice by providing a cost-efficient these cases there may be some incidental
specialised post mortem examination findings that could provide the submitting
(PME) service. RVC-FAPD is a partner vet with better insight into the needs of the
post mortem provider to APHA and as such flock, such as the presence of lice, mites or
PMEs of backyard poultry can be offered at nematodes.
a government subsidised price (currently The two main vets involved with RVC-
£46 + VAT). Figure 1b: Subtle thickening of the left sciatic FAPD and dissections of backyard chickens
nerve in a chicken due to Marek’s disease are myself and Dr Bernat Marti-Garcia. We
are always interested in discussing any
Some gross PME findings in these cases potential PME and diagnostic queries in
of Marek’s disease we encountered can be poultry or other farmed animals with vets.
obvious, with lymphoma in various organs, You can find further information, including
(Fig.1a) but others, including thickening of our contact details, on the RVC Pathology
nerves, can be more subtle and subjective and Diagnostic Laboratories web pages.
(Fig. 1b). Histopathology, especially of the Please note that we cannot accept any
peripheral nerves (sciatic and axillary), was cadavers of birds suspected of having avian
required to confirm the diagnosis of Marek’s influenza (or Newcastle disease). In these
disease. cases, you will first have to notify APHA
Another clinical example of our (03000 200 301).
investigations includes diagnoses of If you are dealing with a tricky clinical
infectious laryngotracheitis (ILT); a case in live backyard chickens, consider
severe, often fatal respiratory disease of contacting the RVC Exotics Service on
chickens that can affect several backyard exoticscamden@rvc.ac.uk for advice.
chickens in a flock. Often these cases
had been associated with a recent history
of introduction of new birds. PME findings For the Diagnostic Pathology Service,
Figure 1a: Markedly enlarged liver with can be striking (Fig. 2a and b), with plugs please call:01707 666 208
multifocal white lymphoma nodules in a Email:
chicken with Marek’s disease diagnosticlabs@rvc.ac.uk

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