A power outage at a poultry farm was studied to examine its effects on caged birds in winter conditions. A monitoring system was installed to measure carbon dioxide and temperature levels at different locations in the house. The results showed that carbon dioxide levels rose rapidly within the first few hours, reaching lethal levels first for birds in the upper tiers. Regular backup generator maintenance and an automatic roof opener invention are recommended for minimizing damage during electricity failures.

1. E
lectricity failure is a major threat facing poultry
producers. It may be a rare occurrence in
countries with a good power supply system but
it is a real and frequent problem in some areas. As a
result, back-up electricity generators are in use on
almost all farms around the world. Nevertheless,
sometimes the unexpected happens - the back-up
system also fails and disaster looms.
A few years ago, a study was conducted on a
research farm to examine the effects of an electricity
failure on growing caged birds (hens) in winter when
the outside temperature was below zero. Which birds
were the first to be affected? What was the cause of
death - carbon dioxide or ammonia build-up or
excessive temperatures? It had been general practice
in that region to maintain the temperature in the
house by turning off the ventilation system and
sealing any cracks in the building.
TTrriiaall sseett--uupp
To measure the carbon dioxide concentration in
the poultry house, a gas collection system was fitted
into poultry house, as shown in Figure 1. Five sets of
filters were placed in different locations and at
different heights on the cages and exhaust fan (Figure
2). Each filter was connected to a PVC tube, which
was in turn connected to a main panel with valves.
Each valve controlled one filter. All five tubes led to
the service room of the poultry house. A vacuum
compressor was connected to the main valve panel
through a fin filter. The compressor pumped the air to
an aquarium, which was upside-down and samples
were taken from another tube placed on the base of
aquarium.
There was a further filter outside the poultry house
to flush the system with fresh air after each sampling.
The samples were analysed chemically, using a
commercial colorimeter and carbon dioxide tube
model 126SA with a range of 0.1-2.6%. Measurements
with low readings were repeated and the average
value was used.
HHooww ddoo bbiirrddss rreeaacctt ttoo aa ppoowweerr ffaaiilluurree??
After an electricity failure, the birds will initially
breathe normally. When the oxygen concentration in
the air begins to fall, they start to breathe more
rapidly for two reasons: firstly, the temperature in the
house increases because of the birds’ body heat and
28 POULTRY INTERNATIONAL SEPTEMBER 2002
Electricity failure –
limiting the damage
Electricity failure –
limiting the damage
A power cut shuts down the ventilation system, leading to a build-up of carbon
dioxide and rising temperature, often with dire consequences for the birds.
Regular checking and maintenance of the back-up electricity generator is
essential. The author has invented a system to keep the birds more comfortable
until the power supply is re-established. —Dr Dhia Alchalabi
Filter
Filter
Compressor
Aquarium
PVC Tube
Valves
Figure 1 Carbon dioxide collection system Figure 2 Filter locations in the poultry house
1
2
3
45
6
7
89
10
11
1213
14
15
16
1
2
3
5
4

2. 30 POULTRY INTERNATIONAL SEPTEMBER 2002
Electricity failure
Figure 3
Figure 5 Figure 6
Figure 4

3. the lack of air movement and exchange and secondly,
carbon dioxide causes an increase in breathing rate
when it is present in high concentration. This results
in a vicious circle as the birds breathe ever more
quickly to get more oxygen but at the same time, this
raises the carbon dioxide concentration and the
house temperature further. Without an emergency
ventilation system, the conditions become lethal.
IInntteerreessttiinngg rreessuullttss
Figures 3 to 6 show the carbon dioxide and
temperature levels at the different locations in the
poultry house after all the fans have been switched
off.
Figure 2 shows the results from location 2. As the
electricity fails, the carbon dioxide level is at an
acceptable 0.21% but after just 40 minutes, it has
risen to 0.90% in the danger zone and the
temperature is close to 29°C. The birds will be under
stress. After another 40 minutes, carbon dioxide has
reached a lethal level of 1.40% and the temperature is
over 31°C as the birds are now breathing rapidly to get
more oxygen and get rid of body heat. The birds will
be restless and noisy. After a further 40 minutes, the
temperature and the carbon dioxide levels at that
location will be unbearable and the weaker birds will
die from the combined effects of heat and carbon
dioxide.
The picture is similar at locations 3 and 4 (Figures 4
and 5) but with higher levels of carbon dioxide and
temperature. Location 5 (Figure 6) was a little
different because here, carbon dioxide and
temperature increased more rapidly. After just 30
minutes, the level of carbon dioxide was already four
times greater than at location 2, and three times
higher than location 3.
This indicates which birds suffer first in the house
with a power failure. In less than two hours under
these conditions, the birds will start to die, starting
from the upper tiers because of the combination of
temperature, relative humidity and the build-up of
carbon dioxide.
Although the carbon dioxide concentration almost
doubled in less than two hours, the ammonia level
hardly changed from the normal level of 20 ppm.
The trial was terminated at that stage to save the
birds. By using emergency fans, the temperature and
carbon dioxide level were back to recommended
levels within 10 minutes.
MMiinniimmiissiinngg tthhee ddaammaaggee wwhheenn tthhee ppoowweerr ffaaiillss
The best method of prevention is regular checks on
the back-up generator. The system must be run for at
least 30 minutes, for example, each times the house is
empty between batches. This ensures the system is in
Electricity failure
See us at
Eurotier 2002
Hall 17 Booth B36

4. good condition and can handle a long run. Keep a
supply of spare parts, e.g. belts, filters, oil. Check the
battery charger and make sure that the batteries are
always fully charged. Clear and clean the electricity
generator shed and do not store other items there.
Follow local regulations on storing flammable
materials and fluids. The shed should have a good
waterproof and well-insulated roof.
Failure of the power system may seem highly
unlikely where all systems are fully computerised and
there is high-tech equipment to run the various
systems. However, this is does not apply in all cases
and from my experience, accidents happen even on
the most sophisticated farms. Faults go unrecognised
during regular maintenance and checks.
AAuuttoommaattiicc rrooooff ooppeenniinngg
One way to prevent disasters is with an automatic
roof opener (ARO). One type has been invented by the
author. It operates mechanically in case of electricity
failure. The idea is simple and practical. The ARO
works by an electromagnetic field generated by a
strong coil when the power supply is operating,
keeping the roof vent closed. When the electricity
fails, a rod is released by the spring, allowing some
natural ventilation of the house. The operation of this
ARO is shown in Figure 7.
Dr. Dhia Alchalabi, poultry environment
consultant, New Zealand.
Further information on the ARO system is available
from the author
34 POULTRY INTERNATIONAL SEPTEMBER 2002
Electricity failure Rod
Spring
Coil
On
Off
Emergency Auto-roof opener
On
Emergency Auto-roof opener
Off
Figure 7 Design of an automatic roof opener
Normal operation
See us at EuroTier 2002 Hall 26 Stand B14