1. Stocking
density
In our 1992 broiler
report, we recommended “that 34 kg/m2 is retained as the maximum
stocking density”, although we conceded that the “absence
of scientific evidence leads us to recommend that further R&D should
be undertaken into stocking density for broilers with particular reference
to welfare.” FAWC will have difficulty in endorsing a stocking
density above our previous recommendation without good reason. FAWC
is pleased that R&D has been undertaken. This has led us to conclude
that an upper limit on stocking density is still necessary. However,
it appears that merely depending on absolute values for stocking density
without a more holistic assessment of the farming operation and poultry
unit is not sustainable. In many ways, therefore, FAWC welcomes the
integrated approach adopted in the draft Directive, especially in terms
of setting a targeted range for stocking density with producers having
to justify (on the basis of key technical factors and indicator-based
monitoring) stocking at the upper limits of the range. However, we still
have some concerns about the practical implementation of such a system,
the stocking density limits set and the welfare outcomes chosen in the
draft (see later comments).
The adoption of
a maximum stocking density above that originally recommended in our
1992 report might be sustainable if robust welfare outcomes can be used
to confirm no significant damage to bird welfare in birds kept at the
highest stocking density. FAWC members might be comfortable with the
integrated approach and a robust audit system suggested, sufficient
that an upper limit of 38 kg/m2 may be sustainable. However, the devil
is in the detail. For example, it is unclear exactly what the penalty
for exceeding the maximum stocking density may be. We understand that
the individual poultry house will be the “unit” defined
under the Directive. Given that broiler growing is a biological phenomenon,
that mortality rates cannot always be predicted accurately, that thinnings
will complicate the calculation and given the inherent inconsistencies
that can arise in placing chick numbers in a poultry house, considerable
resource may be expended on occasions where even the maximum stocking
density is exceeded to some modest degree.
FAWC is attracted,
by these factors and other practicalities, to suggest that the assessment
of stocking density is made on an annual basis as a summary of average
stocking density across the site over that timescale. Anything more
prescriptive is unlikely to benefit animal welfare, unless individual
houses exceed the maximum agreed stocking density by a significant margin,
especially if accompanied by evidence from the indicator based monitoring
that welfare has been compromised. It is imperative that any agreed
rolling average must also be accompanied by an absolute density that
cannot be exceeded in any crop.
In conclusion on
stocking density, we are minded that the interpretation of Marian Dawkins
work does not allow us to automatically conclude that a figure of 38
kg/m2 is “acceptable” but equally there is no evidence that
stocking at this density must be unacceptable. FAWC may be in a better
position to support the proposals in the draft Directive once the results
of the Bristol project are available and Defra is able to give FAWC
more detail as to how they see any programme of audit and approval working
in practice. Definitive approval by FAWC for the stocking density range
in the draft Directive would therefore be premature at this stage. FAWC
is very keen to discuss this with you further in light of such information
becoming available.
2.
Mortality and culls
Accurate mortality
rates should give a reasonably robust indicator of disease status in
a poultry unit, and this is clearly one of a number of useful outcome-based
assessments of bird welfare. Furthermore, culling rates can be an additional
useful factor, especially as the majority of culling on broiler farms
are usually categorised as “leg culls” giving potentially
an assessment of lameness on a particular unit.
The draft proposal
sets a limit that mortality must not exceed 1% plus 0.06% x slaughter
age of the flock in days. By way of example, this calculation indicates
maximum mortality figures as follows:
| 35
days (1% plus 0.06% x 35) |
Max
mortality = 3.10% |
| 36 days |
Max mortality
= 3.16% |
| 37 days |
Max mortality
= 3.22% |
| 38 days |
Max mortality
= 3.28% |
| 39 days |
Max mortality
= 3.34% |
| 40 days |
Max mortality
= 3.40% |
| 50 days |
Max mortality
= 4.00% |
These mortality
limits are not generous but should be achievable as an average
mortality rate on the majority of farms. However, as average figures
then almost by definition 50% of results would be expected to exceed
this limit! Furthermore, the pattern of mortality is significant in
welfare terms. As an example, high early acute mortality due to yolk
sac infection may be less severe than later protracted respiratory disease.
In addition, yolk sac infection may reflect a problem independent of
anything the individual producer can control and is clearly not relevant
to stocking density.
Another significant
aspect in relation to bird welfare is that these figures are expected
to include those birds culled on site. As a result of this tight limit
and the far more generous dead on arrival limit stated in the draft,
it might reasonably be considered that culling rates on farm would fall
to help meet the targets set above, which could not be considered to
be in the interests of bird welfare. Culling policies that protect bird
welfare should not be discouraged or penalised.
It may be necessary
for further consideration to be given to setting slightly higher specific
limits for both mortality and culling, whilst retaining some average
target and absolute figures. As with stocking density, whereas a rolling
average mechanism is attractive in logistical terms, an upper action
limit needs to be imposed (say, 2 standard deviations of average performance)
to avoid potential welfare problems being masked for particular crops.
FAWC feels that this area requires further discussion and clarification,
especially with industry, to achieve a practical and meaningful outcome.
3. Lighting
Annex 1 of the draft
Directive sets out requirements applicable to all establishments covering
requirements for provision of feeding and drinking equipment, and environmental
control. FAWC welcomes the majority of these requirements as representing
best practice.
One area that is
not in tune with current industry practice is in relation to lighting
patterns and especially lighting intensity. FAWC in its 1992 report
recommended uniform levels of light in the poultry house and the provision
of a dark period. Furthermore, we stated that “a suitable
average light intensity is likely to be at least 20 lux throughout the
house at bird eye height and the industry should be encouraged to adopt
this level of illuminance: the absolute lowest average light intensity
which is acceptable to the Council is 10 lux and this minimum should
be introduced immediately.” This has been, in the main, incorporated
into the DEFRA Code of Recommendations for the Welfare of Livestock:
Meat Chickens and Breeding Chickens as “Chickens should be
housed at light levels which allow them to see clearly and which stimulate
activity. This should be provided by lighting systems designed, maintained
and operated to give a minimum light level of 10 lux at bird eye height.
Illumination of the house to at least 20 lux will further encourage
activity.”
We also recommended
that further R&D should be undertaken “to determine the
optimum light intensity and pattern for broiler chickens which will
minimise welfare problems.” A DEFRA funded project on lighting
and visual perception (AWO225) at Silsoe appeared to confirm that the
lighting environment specified in the Code of Recommendations are correct
and can be justified scientifically in terms of the biological mechanisms
tested in this project, although indeed this work was carried out in
laying hens rather than broilers. We understand that further work in
broilers is in progress, and this may help in further deliberations.
In the meantime, FAWC would suggest that the proposals laid out in the
DEFRA Code are appropriate and that the rigid implementation of “at
least 20 lux” in the draft Directive is overly prescriptive.
In terms of dark
period, the Bristol work seems to show a correlation with increasing
length of the dark period and improvement in gait scores. Many observers
agree that bird activity and leg health are improved by introduction
of intermittent lighting patterns over and above the old “1 hour
dark in every 24 hours”. However, the evidence for an optimal
dark period does not appear available from current scientific evidence.
FAWC are supportive of the use of longer dark periods, but whether this
should be 4 or 8 hours is still open to debate. Whatever period is chosen
it would seem that certainly an introduction of an 8 hour dark period
at 3 days of age would be detrimental to bird welfare. The young chick
is still needing to find feed and water at all times and we feel that
bird development would be better served if such a lighting programme
was not introduced until the birds are 7 days of age. Similarly, to
improve welfare at catching, on the basis of best industry practice,
reducing the length of the dark period in the last 7 days (rather than
3 days in the draft) reduces bird activity and damage during the catching
process.
4. Welfare
outcomes
During our discussions
with Marian Dawkins on the conclusions of the Oxford research, FAWC
Poultry Issues Group came to the conclusion that outcome based assessments
of welfare are what is really needed to come to conclusions on the welfare
impact of specific rearing conditions. The problem highlighted was determining
an outcome that could be consistently recorded and categorised and realistic
limits be set on maximum allowable levels.
The factor set in
the draft Directive is that of the incidence of scored foot pad dermatitis.
The choice of the Swedish system sets a rather “all or nothing”
scoring system (absent, mild, severe). FAWC Poultry Issues Group is
aware of industry concerns that mild foot pad dermatitis is seldom directly
related to stocking density per se. On the other hand,
severe footpad dermatitis (like hockburn) may be more useful in assessing
litter condition and hence, indirectly, ventilation, control, nutritional
aspects and husbandry factors in litter and drinker management. Therefore,
the punitive action of reducing stocking density for flocks exceeding
specified foot pad lesion scores may not address the underlying welfare
problem unless the system of scoring truly reflects the severity of
the footpad lesion. As a result, FAWC considers that if foot pad dermatitis
is to be used as part of the indicator based monitoring system of flocks,
the scoring system needs to be consistent and reproducible and the results
used to alert the producer and his veterinary surgeon to the variety
of factors involved, rather than simply concentrating on reducing stocking
density as the solution. Further scientific research into the causes
of footpad dermatitis and discussions with the industry would be advisable
before confirming the exact system.
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