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A. SALAHI, M. MOOSANEZHAD KHABISI, A. PAKDEL, A. BAGHBANZADEH
159
Turk. J. Vet. Anim. Sci.
2012; 36(2): 159-167
© TÜBİTAK
doi:10.3906/vet-1101-750
E ects of cold stress during transportation on hatchability and
chick quality of broiler breeder eggs
Ahmad SALAHI1,*, Mozhdeh MOOSANEZHAD KHABISI2, Abbas PAKDEL3, Ali BAGHBANZADEH4
1Department of Animal Science, Varamin–pishva Branch, Islamic Azad University, Varamin, Tehran - IRAN
2Department of Animal Science, Kahnooj Branch, Islamic Azad University, Kahnooj, Kerman - IRAN
3Department of Animal Science, Faculty of Agricultural Sciences and Engineering, University of Tehran, Karaj - IRAN
4Section of Physiology, Department of Basic Sciences, Faculty of Veterinary Medicine, University of Tehran,
Tehran - IRAN
Received: 26.01.2011
Abstract: In this experiment 72,000 broiler breeder eggs (Ross 308 strain) collected from 36-week-old ocks were
subjected to cold stress during transportation. Eggs were allocated to 4 temperature groups (treatments): 1.2 °C, 1-2 °C,
2.5-3.9 °C, 4-6 °C, and a control group, 21-22 °C. Each treatment had 14,400 eggs, and data were analyzed in a completely
randomized design. e results of this study showed that cold stress had a signi cant e ect on percentage of egg weight
loss (P < 0.001), and minimal egg weight loss occurred in the control group. e percentage of exploders and early
hatched chicks and chick weight were higher in the below zero temperature treatment than the other groups (P < 0.01).
Cold stress had a signi cant e ect on chick length, hatchability, and the hatching of fertile eggs (P < 0.001). e e ects
of cold stress on chick yield and body weight uniformity were signi cant (P < 0.01). e e ect of cold stress on hatchery
byproduct e ciency was signi cant (P < 0.001), but did not a ect fertility. Cold stress also had signi cant e ects on
early (1-8 days), middle (9-17 days), and late mortality (20-21 days); total embryo mortality; and exposed brain. Ectopic
viscera was signi cant (P < 0.001), and most mortality was observed in below 4 °C treatments. Total percentages of
malpositions and deformity (P < 0.001) and egg contamination at 1-9 days ( rst stage) and 10-21 days (second phase)
were a ected by cold stress (P < 0.001). Cold stress also had a signi cant impact on the number of cull chicks; percent of
string navel, button navel, total string, and button; omphalitis; full body cavity; red hocks; dehydration; dirty chickens;
and stubby down. Cold stress a ects performance during incubation and overall chick quality.
Key words: Cold stress, egg transportation, hatchability, chick quality, malposition and deformity, culls, egg weight loss,
embryo mortality and contamination
Research Article
* E-mail: ahmad.salahi2010@gmail.com
Introduction
Incubation provides proper conditions for fertile eggs
to produce high quality day old chicks. is occurs
when the fertile eggs are delivered under standard
conditions from breeder farm to hatchery (1,2). It is
necessary to protect hatching eggs against any heat
or cold stress during collection in the barn; storage
at the farm; and transportation to the hatchery, egg
grading room, incubator, and hatcher. For example,
Cobb-Vantress, Inc—one of the primary breeders—
E ects of cold stress during transportation on hatchability and chick quality of broiler breeder eggs
160
recommends that the temperature of trucks delivering
hatching eggs from farm to hatchery be between 20
and 23 °C (3).
Temperature is one of the important factors
a ecting the growth and development of the embryo
at all stages of the incubation period. e optimum
temperature for fertile eggs during the storage period
depends on the age of eggs, the age of broiler breeder
ock, and the genetic strain of the birds (1-4). It must
be noted that, as storage time increases, hatching eggs
should be stored at lower temperatures. Guidelines
are provided by primary breeder companies. For
instance, Aviagen recommends storing eggs 1-3
days or older (e.g., 4 days) at 19 °C and 16-18 °C,
respectively (5).
It has been shown that storing eggs at −18.33 °C
for 10 h reduced the internal temperature of the eggs
to −1 °C. However, this did not have any impact on
hatchability rate (6). Storing turkey hatching eggs at
−18.33 °C for 1, 2, 3, and 4 h led to a higher number
of female embryos compared to eggs stored from 10
to 12.7 °C; when the temperature was reduced to −16
°C, hatchability decreased (7). If the temperature of
the egg center over 120 min reaches −7 to −10 °C,
embryos will develop normally until they reach 8 days
of age (6). Keeping eggs at −3 °C for 4 days resulted
in the development of the embryos to the blood ring
stage—with a wide and enlarged blastoderm—a er
which only the ectoderm and endoderm had the
opportunity to grow (6). Wilson (8) showed that cold
stress (−2 °C) before incubation increased embryo
mortality, and the peak of mortality occurred a er 16
days. Lundy (9) showed that eggs maintained at −2
to −3 °C caused ice crystal formation, which led to
irreversible damage to embryo tissues.
Deeming (10) reported that cold stress reduced yolk
consumption by the embryo. It also prevented growth
of the embryo and reduced the water loss or vapor
exchange of the egg surface. A reduction of ambient
temperature in broiler breeder hens increased food
consumption and serum corticosterone. It reduced
egg production; feed e ciency; and concentrations
of some vitamins, minerals, insulin, ascorbic acid,
alpha tocopherol, and retinol in plasma. However,
the level of malondialdehyde; the production rate
of free radicals; and requirements for vitamins A, C,
and E increased (11-14).
Cold stress caused weakness in lymphoid organs
and decreased immune function in hens. e e ects
of cold stress in chickens can be produced by di erent
mechanisms. e cold changes the endocrine
system; the hypothalamus-pituitary-adrenal axis,
sympathetic-adrenal-medullary axis, and the
thypothalamus-pituitary-thyroid axis become active,
and, as a result, hormone responses to stress will
be evident. Cold stress caused a signi cant drop in
corticosterone levels and a ected cellular immunity,
but had no e ect on T4 (15).
Several climate changes may take place during
egg transportation. From an economic perspective it
is a very important issue for day old chick producers.
erefore, in the current study the e ects of cold
stress and freezing conditions on broiler breeder eggs
during transportation, and subsequent chick quality
and incubation characteristics were investigated.
M at er ia l a nd me th o ds
e altitude of Tehran Province, where the
experiment was carried out, is 972 m. e experiment
started in January, when the ambient temperature
during delivery of the hatching eggs to the hatchery
was about −15 °C. Due to road closures as a result of
cold weather conditions, all eggs were kept inside the
truck for 40 h. Internal temperature of the eggs was
measured by thermometer (in 144 eggs, by breaking
the eggs and measuring the temperature at the large
end). e thermometer (Testo, Co.) was capable of
measuring temperatures from −40 to 230 °C, with
accuracy to 0.1 °C. Temperature recording for each
egg took about 90 s. We did our best to minimize the
e ect of ambient temperature on the thermometer.
A total of 72,000 fertile and settable eggs were used
in this study. Of this total number, 12% (equal to 48
cartons) were selected; 3 eggs from each carton. In
total, the internal temperatures of 144 eggs (48 × 3)
were measured.
ere were a total of 4 treatments (temperature
group) −1.2 °C, 1 to 2 °C, 2.5 to 3.9 °C, 4 to 6 °C,
and a control group, 21-22 °C. Each treatment had
3 replicates, and each replicate contained 4800 eggs
(equivalent to a Petersime trolley). Each treatment
had 14,400 eggs in total. In a completely randomized
design, eggs were evaluated a er 11 h prewarming
A. SALAHI, M. MOOSANEZHAD KHABISI, A. PAKDEL, A. BAGHBANZADEH
161
and then set in the incubator. From each treatment
720 eggs (3600 eggs total) were individually weighed
by digital scale (Berlini, model KV 2001).
Egg prewarming or preheating was completed in
11 h which is 2 h more than the usual time allotted.
In order to synchronize and prevent delay in the
removal of chicks from the hatcher, the egg setting
was changed to 1 h earlier than the usual time. Every
e ort was made to prevent eggs from sweating while
they were still in the preheating room.
Eggs were individually weighed while in the setter
and at the time of transfer from setter trays to the
hatcher, at day 19 of incubation (19 days plus 6 h). In
the incubator, eggs usually lose part of their weight
as water vapor (egg weight loss) (4). To calculate the
percentage of egg weight loss, the following formula
was used:
wt = weight; pre = at beginning of prewarming;
trans = transfer day.
It must be noted that we calculated prewarming
weight and not setting weight, as there might have
been some weight loss during the 8 to 11 h of
prewarming. In order to determine fertility, we
candled the eggs at day 18 of incubation. Cobb-
Vanress, Inc. recommends candling between days
10 and 12 of incubation (3); however, the Aviagen
management guide indicates that the right time for
candling is day 18 of incubation (5).
Measuring chick length is a fast method for
evaluating chick quality (16). We measured from
the beginning of the beak to the end of the middle
toe by ruler. Chicks were stretched along a ruler by
HatchTech method (16). According to Molenaar
(16), only 25 chicks are needed to measure length;
however, we evaluated 150 chicks. We calculated the
chick yield (%) or chick weight/initial egg weight
ratio from this formula (4):
We also performed an egg breakout on unhatched
eggs (equivalent 20.83% of total), and results were
recorded and evaluated. A er the hatch, all residue,
dead embryos, debris, culls, and shells were collected
in order to prepare them for the production of
hatchery waste. During this process, the above-
mentioned materials are heated to 200 °C for 5 to
6 h in the processing tank, and the end product is
milled into hatchery waste (hatchery by product).
All data were analyzed with SAS so ware version
9.1. Statistical models used for data analysis were as
follows (17):
Yij = μ + Ti + Eij Yij = observation ij
μ = mean of observations (overall mean)
Ti = e ect of i treatment [i = 1, −1.2 °C, i = 2, 1
to 2
°C, i= 3, 2.5 to 3.9 °C, i= 4, 4 to 6 °C, and i = 5,
control (21 to 22 °C)] Eij = experimental error
Results
Our data showed that the rate of egg weight loss
during transportation from farm to hatchery was
1.49%. It must be mentioned that the ambient
temperature during transport from broiler breeder
farm to the hatchery reached below zero. is did not
cause freezing in the egg yolks or albumen; however,
wrinkling of the vitelline membrane and color spots
in egg yolks (manifested as darker or lighter areas)
were observed. In this study egg weight loss was
a ected by temperature (P < 0.001), and maximum
weight loss (14.20%) was found in treatment 2. A
number of contaminated eggs exploded during the
transfer stage or incubation. In this study, percentage
of exploded eggs was in uenced by temperature (P
< 0.01); most exploders (0.05%) were in treatment 1.
e number of early hatched chicks in the incubator
was signi cantly higher in treatment 1 (P < 0.001)
than in other treatments. Some chicks pipped the
outer shell of the egg while still in the incubator. Under
normal conditions we observed 1%-1.5% of eggs in
this situation. As indicated in Table 1, cold stress did
not have a signi cant e ect on eggs pipped. e e ect
of cold stress on chick weight was signi cant (P <
0.01), and mean weight of chicks in treatment 1 (−1.2
°C) was higher than in other treatments. Moreover,
chick yield in treatment 1 was higher than in other
treatments (P < 0.01). Chick length was a ected by
cold stress (P < 0.001); minimum chick length (17.90
cm) was observed in treatment 1, and the greatest
chick length was found in the control group. Chick
length decreased with reduction in temperature
during transport.
Egg wt pre
Egg wrt pre Egg wk trans 100
–#
()
()
Initial egg weight
Chick weight g
2100#
E ects of cold stress during transportation on hatchability and chick quality of broiler breeder eggs
162
As shown in Table 2, hatchability and hatch of
fertile eggs decreased as the severity of cold stress
increased. Cold stress had a signi cant e ect on
percent hatchability and hatch of fertile eggs (P <
0.001). Cull percentage and hatchery byproduct
e ciency increased when temperature was reduced
(P < 0.001); cold stress also signi cantly reduced the
percentage of chick weight uniformity (P < 0.01).
As presented in Table 3, increase in cold stress
before incubation resulted in a signi cant increase in
the rate of contamination (P < 0.001). Cold stress also
a ected total embryo mortality (P < 0.001), and, with
decrease in temperature below 4 °C, total mortality
increased. Reducing the temperature did not a ect
the infertility rate of eggs. Ectopic viscera (ECV) is a
condition in which the intestines appear outside the
abdominal cavity when the chicken is fully developed
(4). In this study, cold stress signi cantly a ected the
incidence of ECV (P < 0.001); with a decrease in
temperature, the rate of ECV increased.
As shown in Table 4, most malpositions (1.10%)
were observed in treatment 1. It seemed that
temperatures below 2 °C increased the incidence
of malpositions. Total malpositions and also head
between thighs, beak above right wing, and head
under le wing increased. Cold stress caused a
Table 1. E ect of cold stress on performance and chick quality.
Treatment Initial egg
weight (g)
Egg weight
loss (%)
Exploder
(%)
Early hatched
(%)
Egg pipped
(%)
Chick weight
(g)
Chick length
(cm)
Chick yield
(%)
161.76 13.66a0.056a0.016a0.66ab 42.83a17.90c69.35a
261.80 14.20a0.015b0.0066b1.206a41.67b17.98c67.43bc
361.77 13.52a0.015b0.00c1.14a41.53b18.07c67.23bc
461.83 14.06a0.023b0.0046bc 1.19a41.34b18.30b66.86c
Control 61.71 12.16b0.020b0.00c0.02b41.93b18.61a67.95b
SEM 0.187 0.222 0.0053 0.002 0.292 0.210 0.079 0.291
P value 0.992 0.0005 0.0012 0.0007 0.0674 0.0042 0.0002 0.0011
a-c : Means within a column without a common superscript di er signi cantly (P ≤ 0.05).
Treatments: 1 = (−1.2 °C), 2 = (1 to 2 °C), 3 = (2.5 to 3.9 °C), 4 = (4 to 6 °C), control =) 21 to 22 °C).
Table 2. E ect of cold stress on hatchability, culls, uniformity, fertility, hatchery by product e ciency.
Treatment Hatchability
(%)
Hatch of fertile
(%)
Culls
(%)
Uniformity of chick
weight (%)
Fertility
(%)
Hatchery by product
e ciency (%)
185.40e87.31d1.84a73.63d97.81 51.35a
286.39d88.28c1.49b77.57cd 97.85 51.19ab
386.85c88.72c1.21c80.36bc 97.89 51.02bc
487.84b89.86b1.09d82.50ab 97.75 50.96c
Control 90.36a92.58a0.84e85.33a97.60 50.30c
SEM 0.095 0.219 0.029 1.400 0.250 0.070
P value <0.0001 <0.0001 <0.0001 0.0014 0.9262 <0.0001
a– c Means within a column without a common superscript di er signi cantly (P ≤ 0.05).
(Treatments: 1 = (–1.2 °C), 2 = (1 to 2 °C), 3 = (2.5 to 3.9 °C), 4 = (4 to 6 °C), control =) 21 to 22 °C)
A. SALAHI, M. MOOSANEZHAD KHABISI, A. PAKDEL, A. BAGHBANZADEH
163
signi cant increase in the rate of malpositions in
treatments compared to the control group (P < 0.001).
As indicated in Table 5, cold stress caused
signi cant increases in the incidence of chicken
deformities in treatments compared to the control
group.
As shown in Table 6, cold stress signi cantly
increased the number of chicks culled due to
conditions such as red hocks, button navel,
summation of button, and string navel.
Discussion
e vitelline membrane contains many proteins,
carbohydrates, and lipids. Eggs stored for 6 months
at temperatures ±1 °C experience weight loss, loss of
nitrogen, and changes in the chemical composition
of vitelline (18). e vitelline membrane loses its
natural state (selective nature) between 20 and 30
days of storage (19). A er 6 weeks eggs stored at 4
°C showed a decrease in the elastic properties of the
vitelline membrane; this resulted in problems that
Table 3. E ect of cold stress on infertility, embryo mortality, and contamination.
Treatment Infertility
1-8 days
(early
mortality)
9-17 days
(middle
mortality)
18-19 days
(turned
mortality)
20-21 days
(late
mortality)
T ota l
mortality
Contamination
Ectopic
viscera
1-9
days
(early)
10-21
days
(late)
12.19 6.15a2.20a1.53b0.88a10.77a1.21a1.21a0.28a
22.14 5.24b1.78c2.02ab 0.85b9.90b1.10b0.73b0.17b
32.10 5.47b2.01b2.60a0.84b10.94a1.00c0.66c0.13c
42.25 4.39c1.08d2.59a0.81c8.87c0.58d0.67c0.09d
Control 2.40 3.48d0.87e1.86b0.78d7.00d0.24e0.12d0.04e
SEM 0.250 0.149 0.043 0.179 0.005 0.130 0.019 0.006 0
P value 0.9262 <0.0001 <0.0001 0.0065 <0.0001 <0.0001 <0.0001 <0.0001 < 0.0001
a– c Means within a column without a common superscript di er signi cantly (P ≤ 0.05).
(Treatments: 1 = (–1.2 °C), 2 = (1 to 2 °C), 3 = (2.5 to 3.9 °C), 4 = (4 to 6 °C), control =) 21 to 22 °C)
Table 4. E ect of cold stress on embryo malposition.
Tre at ment
Malposition
Head between
thighs
Head in the small
end of egg
Head under
le wing
Head not directed
toward air cell
Beak above
right wing TOTAL
10.39a0.15c0.06b0b0.50a1.10a
20.22b0.48b0.00d0b0.37b1.07a
30.22b0.48b0.06b0b0.13c0.89b
40.17c0.58a0.12a0.02a0.00d0.89b
Control 0.06d0.16c0.04c0b0.00d0.26c
SEM 0 0.015 0 0 0 0.015
P value <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001
a– c Means within a column without a common superscript di er signi cantly (P ≤ 0.05).
(Treatments: 1 = (–1.2 °C), 2 = (1 to 2 °C), 3 = (2.5 to 3.9 °C), 4 = (4 to 6 °C), control =) 21 to 22 °C)
E ects of cold stress during transportation on hatchability and chick quality of broiler breeder eggs
164
facilitated the rupture of the vitelline membrane
(20). Storage time and temperature are 2 factors that
a ect the vitelline membrane. e strength of the
vitelline membrane decreases with increasing storage
time. is may allow nutrients in the yolk to become
available to any microorganism present in the
albumen (21). Wrinkling of the vitelline membrane
in sub-zero temperatures, under cold stress, is in line
with this nding.
Egg water loss during storage has a positive e ect
on hatchability (22). e percentage of egg weight
loss between 1 and 19 days in Cobb 500 and Ross
308 strains is 10.9% and 12.9%, respectively. Age of
the ock (before 44 weeks) does not a ect egg weight
loss, but the e ect of strain is signi cant (23). Egg
weight loss reaches 12% up to 18 days, and as the
altitude increases, the drop in egg weight increases
(3). According to Aviagen, egg weight loss should
be 12% from the time eggs set in the incubator up
to transfer; under these conditions hatchability and
chick quality are ideal. If eggs are stored for more
than 6 days, egg weight loss will reach 11.5% (4).
In the current study, egg weight loss in control eggs
was 12.16%, which conforms to the observations of
Table 5. E ect of cold stress on embryo deformity and disorders.
Treatment Deformity TOTAL
Exposed brain Without eye(s) 4 legs Deformed beak
1 0.22a0c0.13a0.90c1.25c
2 0.11c0.40b0.05ab 2.48a3.04b
3 0.09d0cob0d0.06d
4 0.13b1.33aob2.36b3.82a
Control 0.02e0cob0d0.02d
SEM 0 0.007 0.03 0 0.033
P value <0.0001 <0.0001 0.0396 <0.0001 <0.0001
a– c Means within a column without a common superscript di er signi cantly (P ≤ 0.05).
(Treatments: 1 = (–1.2 °C), 2 = (1 to 2 °C), 3 = (2.5 to 3.9 °C), 4 = (4 to 6 °C), control =) 21 to 22 °C)
Table 6. E ect of cold stress on culled chicks.
Treatment Culls and deaths
String navel Button navel String + button Body cavity full Red hock Dehydrated Stubby down Dirty chicks
11.77e20.79a22.56a58.09d4.29a7.82b4.08d3.15a
26.27c12.79b19.07b56.29e4.18a4.99d12.98c2.49b
312.53b6c18.53b76.36a0d5.10c0e0c
414.47a0e14.47c62.63b1c4.53e17.37a0c
Control 5d2d7d61.56c1.43b11a16b0c
SEM 0.172 0.264 0.292 0.323 0.133 0 0.082 0.038
P value <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001
a– c Means within a column without a common superscript di er signi cantly (P ≤ 0.05).
(Treatments: 1 = (–1.2 °C), 2 = (1 to 2 °C), 3 = (2.5 to 3.9 °C), 4 = (4 to 6 °C), control =) 21 to 22 °C)
A. SALAHI, M. MOOSANEZHAD KHABISI, A. PAKDEL, A. BAGHBANZADEH
165
Aviagen and Cobb-Vantress. When compared with
the control group, cold stress caused an increase
in the egg weight loss. However, there was not a
signi cant di erence between the treatments.
An increase in exploder eggs can be caused by
a dirty nest, egg laying on the oor, egg washing,
using dirty egg cleaner or sandpaper, high levels of
dust in the nest, transportation and cold conditions,
sweating eggs, spraying water on eggs, broken eggs,
hand contamination of egg handlers, contamination
of the setter oor, air lters, and the moisture supply
system (24). e current study demonstrated that
cold stress is another factor a ecting the percentage
of exploder eggs.
Early hatch in the incubator can be attributed
to small eggs, di erences between breeds, as well as
high temperatures and low humidity in the incubator
(24). In the present study, cold stress—especially at
temperatures below zero—increased the rate of early
hatched chicks.
Chick weight is a ected by egg weight (25,26).
A decrease in temperature (from 37.8 to 36.6 °C)
during incubation resulted in an increase in chick
body weight, from 39 to 40 g, and yolk sac weight,
from 3 to 4.3 g (27). ese ndings are consistent
with the ndings of others; there were overweight
chicks in treatment 1 and a lack of yolk uptake and
inappropriate yolk usage.
Chick yield or chick weight-to-egg ratios are
normally between 66% and 68% (3). is ratio in
fresh eggs (stored for a short period of time) was
between 67% and 67.5% (4). Other research reported
chick yield at 36 weeks at 73.1% (23). In the current
study, the chick weight-to-egg ratio was higher in
treatment 1. Improper use of nutrients inside the egg
and yolk sac prevents chicks from growing enough.
A temperature decrease from 37.8 to 36.6 °C during
incubation reduced chick length from 16.8 to 16.3
cm (27). Chick length in this experiment was a ected
by cold stress; reducing the temperature during
transport also reduced chick size.
Percentage hatchability and hatch of fertile eggs
(Ross 308, 36 weeks of age) were 80.8% and 85.9%,
respectively (23). A temperature decrease from
37.8 to 36.6 °C in incubation caused a reduction in
hatchability (salable chicks) from 87% to 81% (27).
In the current study, reducing the temperature level
reduced the hatch of fertile eggs and hatchability. e
rate of cull chicks was 0.97%. Although it was 0.68%
at 38 weeks and 0.42%-0.67% at under 43 weeks of
age, the highest rate was 1.49% at 63 weeks (Cobb
500) (28). In the current study, the percentage of
cull chicks and hatchery byproduct (hatchery waste)
increased as the temperature was reduced.
Uniformity of ock is the percentage of chicks
within ±10% (29) or ±15% (3) of the average body
weight at a certain age. e goal is 80% uniformity
in a ock. Uniformity is a ected by many factors
including egg size, shell quality, genetic variation
of parents, ock density, quantity or quality of feed
consumed, parasites, environmental conditions (nest
temperature), photoperiod programs, feed restriction
programs, broiler breeder body weight (30),
incubator type or model (single stage or multistage),
incubation conditions, duration of egg storage, initial
egg weight, chick room conditions, condition of
trucks and transportation system, variation between
eggs (non-uniform chicks produced from small or
large eggs), mixing eggs from young and old ocks,
mixing eggs from di erent strains, storage periods,
di erent patterns of egg storage, ventilation, non-
uniform setter and hatcher conditions, diseases, and
stress (24). Hatchability in ocks with 55%-59% and
75%-80% uniformity was 69.19 ± 1.93% and 83.93 ±
1.65%, respectively (30). In the current study, cold
stress severely reduced uniformity of body weight.
Egg contamination rates from 0 to 21 days
(in a ock 31-45 weeks of age) were nearly 0.5%
(4). Placing cold stress on eggs before incubation
signi cantly increased the number of contaminated
eggs and chicks with full body cavity.
Cold stress had a signi cant e ect on total
embryonic mortality, and with reduction in
temperature (below 4 °C) the rate of mortality
increased. Reducing the temperature did not
a ect infertility. Egg shell contamination, nest
contamination, ventilation status, and hatchery
disinfection can cause increases in embryo
mortality (31). An increase in the duration of egg
storage, fumigation within 12 to 16 h of incubation,
high or low temperatures, egg damage during
transportation (jarring), illness, an old or aging ock,
contamination, drugs, and pesticides are factors
E ects of cold stress during transportation on hatchability and chick quality of broiler breeder eggs
166
that can increase embryonic mortality (24). Early
embryonic mortality (36 weeks, Ross 308) was 2.5%
(23). A decrease in incubator temperature from 37.8
to 36.6 °C increased early embryonic mortality from
2.7% to 2.8% (27). Mortality at 12-17 days is caused
by inappropriate incubator temperature, moisture,
nutritional de ciency (vitamins, phosphorus, and
linoleic acid), and lethal genes (24). Reduction in
incubator temperature from 37.8 to 36.6 °C increased
embryonic mortality at the middle stage from 0.2% to
0.5% (27). Embryo mortality in the middle stage (36
weeks, Ross 308) was 3% (23). Wilson (25) showed
that cold stress (−2 °C) before the incubation period
increased embryo mortality and most mortality
reported a er the 16th day. In the current study, we
found that early stage embryo mortality in treatment
1 was higher than in other treatments. .
Eggshell pipping can result from upside-down
eggs, setting fumigation at a high concentration,
high temperature, high humidity, low turning, old
eggs, large-sized eggs, and ventilation problems (24).
Embryo mortality at the end of incubation (late stage)
in a 36 week Ross 308 was 1.1% (23).
A reduction in incubator temperature from 37.8
to 36.6 °C increased embryonic mortality at the
pipping stage (beak entering air cell) from 0.8% to
1.4% and at external pipping (tip of beak puncturing
the eggshell) from 0.9% to 2.4% (27). e incidence
of ECV is increased by high incubator temperatures,
inheritance, and lethal genes (24). In the current
study, cold stress signi cantly increased ECV rates.
e quality of chickens during incubation depends
on various factors such as maternal age, ock
status, length of storage and storage conditions, and
incubation conditions (32). Inside the egg a normal
embryo must position itself with the head (beak)
under the right wing and placed directly into the air
cell. Usually 1%-2% of chickens have malpositions
and deformity, and these disorders are observed in
the last week of incubation. In this study, malpositions
occurred in 1.2%-1.8% of chicks (average 1.5%). Most
embryos have a type of malposition that prevents the
use of oxygen and they die in the shell (dead in shell);
only a few of these embryos are able to leave the shell.
Type 6 malpositions account for 48% of malpositions
(beak above right wing); type 5 (feet on the head),
20%; type 1 (head between the thighs), 12.5%; type 2
(head towards the end thin egg), 7.5%; type 3 (head
under le wing), 7.5%; and type 4 (head not directed
toward air cell), 4.5% (33).
Cold stress signi cantly a ected total
malpositions. Most malpositions (1.10%) occurred
in treatment 1. A decrease in temperature towards
−2 °C increased the incidence of malpositions. One
of the important factors a ecting the occurrence of
malpositions is insu cient egg weight loss in the
incubator (33). In the present study, the rate of egg
weight loss in all treatments was higher than in the
control group and the total rate of malposition was
associated with it.
Deformity or abnormalities prevent embryos
from leaving the eggs. e rate of deformity was
0.22%-0.3%. Most abnormalities occur between 15
and 21 days of incubation and include brain hernia
(29%), beak deformity (27%), failure to develop
eyes (25%), 4 legs (10%), lack of upper beak (8%),
and twisted legs (1%). High incubation temperatures
cause abnormalities in the brain and eyes, while
low temperatures a ect chicken growth. At normal
hatchability status (85%) the rate of deformity does
not exceed more than 0.3% (33).
In our experiment, cold stress caused a signi cant
increase in the rate of deformity in treatment groups
compared to the control. Inheritance and viral
infection cause cross beaked chickens and chickens
without eye(s); these and other malformations
are also caused by high temperatures, problems
in egg handling, or delay in hatch time due to low
temperatures during incubation (3). We observed
that cold stress increased dirty chicks, red hock,
button navel, and total string and button navel.
In conclusion, cold stress during the delivery of
eggs from farm to hatchery a ects the performance
of the developing embryo during incubation; cold
stress also impacts chick quality at the time of hatch
and at later stages of life.
Acknowledgement
We would like to thank the manager and personnel at
Mahan Hatchery.
A. SALAHI, M. MOOSANEZHAD KHABISI, A. PAKDEL, A. BAGHBANZADEH
167
References
1. French, N.A.: Modeling incubation temperature: the e ects of
incubator design, embryonic development, and egg size. Poult.
Sci., 1997; 76: 124-133.
2. Nakage, E.S., Cardozo, J.P., Pereira, G.T., Queiroz, S.A., Boleli,
I.C.: E ect of temperature on incubation period, embryonic
mortality, hatch rate, egg water loss and partridge chick weight
(Rhynchotus rufescens). Rev. Bras. de Ciên. Avíc., 2003; 5: 1-5.
3. Cobb-Vantress, Inc.: Guide Management Hatchery. Revised
(Arkansas). 2008.
4. Tullett, S.: Investigating hatchery practice. Ross Tech. Scotland,
United Kingdom. 2009. October.
5. ROSS.: Parent stock management manual. Aviagen Limited
Newbridge, Midlothian, EH28 8SZ, Scotland, United Kingdom.
2006. March.
6. Taylor, L.W.: e care of hatching eggs before incubation
(Chapter 4). In: Taylor, L.W. Fertility and Hatchability of
Chicken and Turkey Eggs. Greenworld Publisher, India. 2003;
150-177.
7. Jull, M., McCartney, AM.G., El-lbiary, H.M.: Hatchability of
chicken and turkey eggs held in freezing temperatures. Poult.
Sci. 1947; 26:545-546.
8. Wilson, H.R.: Physiological requirements of the developing
embryo (Chapter 9). In: Tullet, S.G. Avian Incubation.
Butterworth-Heinemann; London. 1991; 145-156.
9. Lundy, H.: A review of the e ects of temperature, humidity,
turning and gaseous environment in the incubator on the
hatchability of the hen’s egg (Chapter 9). In: Carter, T.C.,
Freeman, B.M., Eds. e Fertility and Hatchability of the Hen’s
Egg. Oliver and Boyd, Edinburgh, UK. 1969; 143-176.
10. Deeming, D.C.: Failure to turn eggs during incubation:
development of the areavasculosa and embryonic growth. J. of
Morphol., 1989; 201: 179-186.
11. Ensminger, M.E., Old eld, J.E., Heinemann, W.W.: Feeds and
nutrition. e Ensminger Publishing Company. USA. 1990;
593-666.
12. Siegel, H.S.: Stress, strains and resistance. Brit. Poult. Sci., 1995;
36: 3-24.
13. Klasing, K.C.: Comparative avian nutrition Cambridge
University Press. UK. 1998; 277-299.
14. Kucuk, O., Sahin, N., Sahin, K., Gursu, M.F., Gulcu, F.,
Zcelik, M.O., Issi, M.: Egg production, egg quality, and
lipid peroxidation status in laying hens maintained at a low
ambient temperature (6 °C) and fed a vitamin C and vitamin
E-supplemented diet. Vet. Med., 2003; 48: 33-40.
15. Hangalapura, B.N., Nieuwland, M.G., Buyse, J., Kemp, B.,
Parmentier, H.K.: E ect of duration of cold stress on plasma
adrenal and thyroid hormone levels and immune responses
in chicken lines divergently selected for antibody responses.
Poult. Sci., 2004; 83: 1644-1649.
16. Molenaar, R.: Evaluation of chick quality: which method do you
choose? Hatchtech Incubation Technology. e Netherlands.
2009.
17. Zamani, P.: Statistical designs in animal science. Bu-ali Sina
University Press, Hamadan, Iran. 2010; 101-123.
18. Trziszka,T., Smoliska, T.: Chemical characterization of the
vitelline membrane of hen eggs. Food Chem., 1982; 8: 61-70.
19. Smoliska, T., Trziszka, T.: e vitelline membrane: dynamics
of cholesterol metabolism hen eggs Food. Chem., 1982; 8: 215-
223.
20. Jones, D.R., Musgrove, M.T.: E ects of extended storage on egg
quality factors. Poult. Sci., 2005; 84: 1774-1777.
21. Akyurek, H., Okur, A.A.: E ect of storage time, temperature
and hen age on egg quality in free range layer hens. J. Anim.
Vet. Adv., 2009; 8: 1953-1958.
22. Walash, T.J., Rizk, R.E., Brake, J.: E ects of temperature and
carbon dioxide on albumen characteristics, weight loss, and
early embryonic mortality of long stored hatching eggs. Poult.
Sci., 1995; 74: 1403-1410.
23. Abudabos, A.: e e ect of broiler breeder strain and parent
ock age on hatchability and fertile hatchability. Int. J. Poult.
Sci., 2010; 9: 231-235.
24. Wilson, H.R.: Hatchability problem analysis, CIR1112,
University of Florida, Gainesville. USA. 2004.
25. Wilson, H.R.: Interrelationship of egg size, chick size, post-
hatching growth and hatchability. World. Poult. Sci., J. 1991;
47: 5-20.
26. Tona, K., Onagbesan, O., De Ketelaere, B., Decuypere, E.,
Bruggman, V.: E ect of age of broiler breeders and egg storage
on egg quality, hatchability, chick quality, chick weight and
chick posthatch growth to forty-two days. J. Appl. Poult. Res.,
2004; 13: 10-12.
27. Joseph, N., Lourens, S.A., Moran, E.T.: e e ects of
suboptimal eggshell temperature during incubation on broiler
chick quality, live performance, and processing yield. Poult.
Sci., 2006; 85: 932-938.
28. Leonor, H., Reis, M., Chaviro Soares, M.: e e ect of candling
on the hatchability of eggs from broiler breeder hens. J. Appl.
Poult. Res., 1993; 2: 142-146.
29. Ensminger, M.E.: Poultry Science. Second Edition. e
Interstate Printers and Publishers, Inc., Danville, Illinois, USA.
1980: 325-326.
30. Abbas, S.A., Gasm Elseid, A.A., Ahmad, M.K.A.: E ect of body
weight uniformity on the productivity of broiler breeder hens.
Int. J. Poult. Sci., 2010; 9: 225-230.
31. Shane, S.: Promoting chick quality and liveability. Am. Soy
Assoc. Tech. Bulletin, 1999; 43: 1-3.
32. Tona, K., Bruggeman, V., Onagbesan, O., Bamelis, F., Gbeassor,
M., Decuypere, E.: Day old chick quality: relationship to
hatching egg quality, adequate incubation practice and
prediction of broiler performance. Avi. & Poult. Biol. Rev.,
2005; 16: 109-119.
33. Butcher, G.D., Nilipour, A.H.: Chicken embryo malpositions
and deformities. Reviewed. University of Florida, USA. 2009;
129: 1-3.
