1. MANAGEMENT
Brooding practice affects
broiler performance
Primary breeding companies are
producing broilers that are
capable of producing more meat
while consuming less feed.
Economic pressures in the
industry are resulting in fewer
staff supervising larger numbers
of broilers. In these conditions it
is increasingly important to
understand the basis of high
level, predictable broiler
performance.
By Alan Tinch and Dinah Nicholson,
Aviagen Ltd.
F
or many years Aviagen has worked
to identify the key factors which determine success in a broiler growing
operation. These key factors are described in its technical literature and allow the broiler grower to maximise performance by meeting the requirements of
the broiler.
Starting in the hatchery
Success on the broiler farm starts in the
hatchery. Recent research has shown that
the high levels of heat produced by fertile
eggs in the late stages of incubation can result in excessively high temperatures within
the hatcher. High temperature at this stage
will stress the emerging chick resulting in
excess weight loss in the hatcher and poorer performance in the broiler house. When
looking for opportunities to improve early
broiler performance, temperature and humidity control of the eggs and newly
emerged chicks should be examined to ensure the chicks are not being heat stressed.
Broiler farm reception
Good broiler performance is dependent on
the chicks getting off to a good start, as soon
as they arrive on the farm. The potential 7day bodyweight of the modern broiler chick is
180g or more and only slightly less in chicks
from younger parent flocks. If the chicks
achieve a good 7-day bodyweight (160g or
more), it is an indication that they have had a
good start. However, if the 7-day bodyweight
is disappointing (140g or less), how can it be
improved?
Measurement of early predictors of success
such as crop fill and 7-day bodyweight are important tools for monitoring and improving
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Brooding practice influences bird
performance during the whole cycle.
(photo: Maywick Ltd.)
broiler performance. Generally, flocks with
poor 7-day bodyweights will also be uneven.
Poor 7-day bodyweights will generally be
due to the chicks being unable to find feed
or water. This may happen when the chicks
are placed, or at the point when they have
to move on from supplementary feed and
water to the automated systems.
Growth rates can also be depressed if the
birds are brooded in high temperatures
(and so eat less), or if the chicks are small.
Guidelines on the temperature and relative
humidity required to keep the chick in its
comfort zone can be obtained from
Aviagen’s technical literature. Shed temperature should be adjusted using chick behaviour as a guide. When 7-day bodyweights
are less than 140g, there are two main areas
to look at when trying to improve conditions for the next flock..
Crop fill
When they first start to feed, chicks will tend
to eat a good meal, which also fills the crop.
The crop is a muscular pouch situated at the
front of the neck at the junction of the neck
and the clavicle (wishbone). The crop fills
with a mixture of food and water if the chicks
are feeding and drinking properly. Gentle
handling of the chicks within the first 48
hours can give a good indication as to
whether the chicks have eaten and had a
drink. Ideally, the crop should be full and
rounded, and the contents should have a soft,
porridge-like consistency. If the crop content
When the feed on the paper runs out before
the chicks have learned to use the feeders, one
must re-feed the paper, giving then more time
to locate the feeders. (photo: Big Dutchman)
is stiff, or the original texture of the feed can
be felt through the crop wall, then these birds
have had little or nothing to drink.
The crop fill target should be:
• 8 hours after delivery 80%
• 24 hours after delivery 95%
If crop fill is below this target, then action
will be needed:
• Put plenty of feed onto paper for the
chicks (aim for 35g/chick).
• Tip the chicks onto the feed on the paper
– do not expect them to find it.
• Make sure that the feed form is suitable –
a sieved crumb.
If any bird seems short of water after 24
hours, then act to improve water availability
by e.g.:
• Adjust water pressure so that there is a
drop of water on each nipple.
• Adjust water pressure so that there is water in the drip trays for the first 24 hours.
• Use supplementary drinkers for the first
24 hours.
Chicks will be less likely to dehydrate if humidity in the house is over 65% for the first
48 hours.
Transfer to automated feeder
system
It is possible to have chicks with a good
crop fill at 24 hours (i.e. more than 95%) but
which still have a disappointing 7-day
bodyweight. When this happens, it is probably because the chicks have had difficulties
moving on to the automatic feeding and
WORLD POULTRY - Elsevier Volume 18, No 10. '02

2. Figure 1. Daily broiler liveweights - 0 -7 days
drinking systems. If this is the case, smaller
chicks will often be the worst affected, simply because they are less able to reach the
feeders and drinkers.
Often, there is a check in feed intake as
the chicks start having to eat from the track
or pans, which is followed a day or so later
by a growth check. Weighing a small sample
of chicks daily will soon show if this is happening; the growth rate will slow and the CV
get worse in the following 2 days.
The graph (Figure 1) shows the growth
pattern of a flock where feed intake stalled
at 2 days, when the feed on the paper ran
WORLD POULTRY - Elsevier Volume 18, No 10. '02
out, before the chicks had learned to use
the feeders. To prevent reoccurrence:
• Re-feed on the paper, so that the chicks
have longer to find the feeders.
• Make sure that the feeder is flooded with
feed, so that the chicks can find feed.
• Watch the chicks when the feeders are
running. Is it clear to them when food is
coming?
Nutrition
For potential 7-day bodyweight to be
achieved the chick requires good nutrition.
Recent research has shown that improved
performance can result from increasing the
protein level in the starter diet. Recent trials
in Aviagen have shown how an increase of
10% in the protein (available amino acid)
level of the starter ration resulted in improved growth to 7 and 42 days, FCR and
uniformity. Breast meat yield was also improved. The increased cost of the starter ration (0-10 days) was more than made up for
by improved performance of the birds.
The digestive system of the young chick is
immature and care must be taken to ensure
that the raw materials used are highly digestible. Total fat levels should be kept low
and saturated animal fats should be avoided. Seven-day bodyweights less than target
are often seen when Starter diets contain
less than 22% crude protein or 1.16% available lysine.
Overall
As broiler performance improves, achievement of target 7-day bodyweight becomes
increasingly important. The major objective
in the first few days of life is to get the broiler chick eating and drinking. When this is
achieved performance will be good. If broiler chicks are prevented from feeding and
drinking by factors in the environment, performance will be depressed. The management procedures described in this article
will encourage the broiler chick to find and
consume high quality feed and therefore
achieve potential performance. □
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