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1. How we investigate afield problem
How do we investigate a sick flock

2. • because
• poultry is most often kept in barns, it closely depends
on
• housing conditions to be healthy. The Koch’s postulate
• ‘one infectious agent, one disease’ thus can be
remodeled
• into this schematization:
• Bird
• Environment Infectious agent
• .

3. Optimal environmental conditions,
access to high quality
feed and water must therefore be
provided for the bird
comfort, which in turn will
translate in maximum efficiency
production and growth

4. poultry veterinarian’s toolbox
you will find a necropsy
kit (e.g. necropsy knife
necropsy shears to cut bones,
Enterotome
to incise the gut, scalpel,
forceps…),
materials
for sampling (e.g. needles and
syringes, blood tubes,
sterile plastic bags and swabs,
specimen containers with
and without 10% phosphate
buffered formalin),

5. possibly
a microscope to look at Eimeria
from gut scrapings,
various instruments to measure air
and water quality,
and the appropriate gears (clean
clothes or disposable
coveralls, disposable plastic boots,
head covering such as
a disposable bouffant, disposable
gloves, hand sanitizer)
to comply with biosecurity
measures.

6. A flock visit
can be done either because
there is a problem
And
the owner has requested your
presence,
or as part
of a routine health check.

7. The most common reasons for a
call
to the poultry veterinarian
are the following:
increased mortality
respiratory clinical signs
presence of diarrhea
lameness
Or
loss in performances.

8. Normal mortality
In the case of an increased
mortality, a greater number of
birds than the usual expected daily
rate die.
This expected
daily mortality does vary according
to
the age of the flock,
the type of birds,
the type of production
and
housing.

10. Normal birds
During the flock visit it is very
important to closely observed
the birds and look for
unhealthy or sick birds.
General
physical and behavioral
observations provide a good
indication.

11. Healthy birds will be alert, active
with bright
round and open eyes. Mature
turkeys and laying chickens
should have a bright red comb.

12. Birds should be clean with
smooth feathers and bright neat
scaly legs.
Feces should
be well-formed, brown or grey with
a white ‘cap’ the
urates.
some shade of brown and fairly solid in
consistency, with a sort of fluffy white cap
on top.

13. During the visit you might also see
on the litter,
pale brown frothy feces which are
from the ceca and can
regularly be observed in the barn

14. Behavior Depending on the
housing system, birds should be
able to
stand, walk, even run, scratch and
sit only for short periods.
Turkeys and ducks do not scratch
the litter and birds in
cage cannot unless provided with a
sand box. Chickens
will quickly walk away from the
unusual visitors while
turkeys will follow them.

15. Young broiler chickens will often
be found fighting i.e jumping at
each other with spread
wings.
Turkeys can show a belligerent
behavior to their
mates but will be hissing,
walking slowly in the crowd with
fluffed up feathers, a blue colored
head with an elongated
snood.

16. Evaluating the body condition
Numerous growth charts
are available and vary according
to the genetic,
management system
and feeding company.
Such charts should be consulted to
verify if the bird’s body
weight and growth rate are within
normal goals.

17. One can
also tell the body condition of a
bird by palpating the breast
muscle.
With the bird held by the legs in
one hand in an
upside down position, use the palm
of the other hand to

18. and the convexity
or concavity of the breast muscle
contour.
palpate the protuberance of the
keel, the development of
the breast muscles alongside that
keel

19. A nice growing
bird will show a convex (rounded)
contour of the breast
with plump breast muscle and no
protuberance of the keel,
while an emaciated bird will show
a marked concavity of
the breast contour caused by a
prominent keel with barely
no pectoral muscles being felt.

20. Clinical signs
Clinical signs will vary
according to the disease
and affected
system(s) and will vary in
severity. Not all birds in a
flock
will exhibit clinical signs

21. . Early in the course of the disease
only a few individuals might be
affected and care should be
taken to find them

22. In general, sick birds are listless,
will sit for long periods,
their head held close to the body,
tail and possibly wings
dropping. Comb and wattles may
be paler and shrunken.
Eyes will be dull and sometimes
closed. They might
not drink nor eat, hence
slowing/stopping growth and
eventually losing weight.

23. Anorexic chickens will often have
green colored feces (due to bile
stain) which might stain
the feathers of the pericloacal area.
Dehydrated birds will
show darker and thinner looking
legs, they will feel lighter
and the skin will not move freely
over the keel.

24. If cold or
Pyrexic feathers will be fluffed,
and birds will huddle in
corners or with others to keep
warm. Uncomfortable chicks
will initially be chirping loudly
before becoming depressed
if source of discomfort is not
corrected

25. If a respiratory disease is suspected,
early on the course
of the disease, chickens will shake
their head and scratch
it with their feet. As the disease
progresses watery eyes
and/or nasal exudate might be
observed and will make the
birds look dirty with the dust and
dirt adhering to the wet
feathers and beak.

26. Swollen infra-orbital sinuses will
affect
shape of the eye and might even
force its closure
Severe respiratory difficulties
might even cause
the bird to extend its neck and
abdominal wall movements
can be observed

27. If an enteritis is suspected, some
birds might have dirty
feathers around the vent that might
be even soiled with
blood or Sulphur colored feces
depending on the infectious
agent. These blood or sculptured
colored feces will also be
found on the litter.

28. Lame birds will spend more time
sitting, and will walk with
difficulties, spreading their wings.
Traumatic lesions will be
observed on the ventral aspect of
the carpo-metacarpal
joint as well as a sternal bursitis in
chronically recumbent
birds. Depending on the cause,
joints might or might not be
swollen and hot. The plantar
surface of the feet might be
dirty, crusted, cracked and/or
reddened.

29. When investigating a loss in
performances,
a reduced body weight
a higher feed conversion
a drop in egg production,
a decreased hatchability
flock results should be carefully
examined and compared to
expected result in order to
define the problem perceived by the
flock manager and
answer the basic questions
who, what, when, where,
how?

30. Barn environment
As stated earlier, the quality of
housing will greatly impact
on the birds’ health. Poultry barns
should provide clean
feed and water, fresh air, protection
against predators,
shelter from cold, rain, wind, sun
and excessive heat; as
well as a source of heat when birds
are young. During the
visit, you can verify the most
important elements using the
acronym F-L-A-W-S. F is for feed,
L for light/litter, A for Air,
W for water, S for
Sanitation/safety/space/staff.

31. Feed.
Feed and water are usually
available at libitum in
meat birds, but quantities are
controlled in breeders and
layers. Feeders and drinkers must
be located at the right
height to optimize access.
Variations in feed consumption
can be indicative of a disease, but
also associated with hot
and cold weather, the feed itself
(energy, fiber, particle size)
or
with the birds’ needs (e.g. point of
lay).

32. Light.The lighting schedule
and light intensity are very
important parameters in laying
birds,
since light stimulates
egg production.
In many meat type birds, daylength
will be
shortened early in life to control the
growth rate.

33. Litter. The litter is a mixture of
feces and bedding material.
The latter should be made of
absorbent material and in
enough quantity for comfort. If too
dry, respiratory problems
will arise while a too humid litter
might trigger intestinal and
skeletal pathologies. A litter is too
humid if it keeps its shape
once you have squeezed a handful
in your fist

34. Air. One of the most important
elements of managing the
environment inside a chicken barn is air
quality and,
in
particular, airflow. Ventilation in the
majority of commercial
barns is mechanical and of the outmost
importance
since any power shortage will rapidly
cause death due
to hyperthermia. Not only good ventilation
will bring
fresh air into the barn, but it will take out
noxious gases
(CO2, ammonia…), dust and humidity.
Poor air quality
will increase in respiratory problems.

35. if the ventilation is poor,
the litter will be more humid, creating an
ideal milieu for certain bacteria and parasites.
You might
then end up with a coccidia challenge or lame
birds.
Barn temperatures are electronically controlled
and monitored
with probes.
There is a comfort zone at which growth is
optimal. Since newly hatched birds are
poikilotherm, a
heat source must be provided. Since birds do
not have
sweat glands and use evaporative cooling via
their breath,
temperature superior to 40oC are very
uncomfortable and
might be lethal when more than 46oC.

36. Water. Drinking water should be of quality
and present
in adequate quantity. Birds generally drink
approximately
twice as much water as the amount of feed
consumed on a weight basis.
Any water restriction will impair feed
intake.
Water consumption will often decrease a
day or two before
the onset of clinical signs. Consumption is
also closely
associated with environmental
temperatures. For example during
periods of extreme heat stress, water
requirements
may easily quadruple.

37. Sanitation. Information
regarding cleaning, disinfection,
pest control, downtime, as well as
previous history of
disease, routine and current
medication, and vaccination
program should be collected during
the visit. Biosecurity
measures should also be in place in
order to minimize the
risk of disease introduction and
spread

38. Space. Birds also need
adequate space for movement
and exercise, access to feeders and
drinkers. Space
requirements vary with the species,
type or breed of birds
that are raised, as well as the type
of production system
used.

39. Staff. An attentive and
skilled farm manager and employee
are of the outmost importance in
the rearing and keeping
of a healthy poultry flock. Any
changes to the management
can adversely affect the birds.