Nutrition, genetic factors, age of breeding flock, illnesses, egg quality,
high altitudes, egg storage and hatching conditions all affect the hatchability
and chick quality. Nearly 6% out of hatchery eggs are obtained from breeding
flocks together with normal shaped eggs. There are 15 kinds of abnormal shaped
eggs and the hatchability of fertile eggs is nearly 48.9% for these eggs (Türkoğlu
and Sarİca, 2004).
Some factors such as heritability, environment, nutrition, hormones, pathology,
flock management, low albumen quality, stress and infectious illnesses might
lead to abnormal egg formation. Higher ration Ca levels, deformation of shell
segregation gland, age, genetic and illnesses lead to formation of rough shelled
eggs. Outer forcing or excessive physical forcing during shell formation lead
to formation of body checked eggs (Dhawale, 2008; Durmuş
et al., 2007).
Cherms and Wolff (1968) reported that race and management
factors had significant role on ratio of abnormal eggs.
Study by taking into account the specific gravity, low specific gravity with
the highest levels of egg weight loss, embryo mortality and low levels hatchability
have been reported (McDaniel et al., 1979).
Egg shell quality has a significant role on hatchability. Many factors affect
the shell formation. These factors affect the shell quality prior to laying
and egg color and shape might be changed due to these factors (Koelkebeck,
Mroz et al. (2007) found the embryo mortality
and hatchability of fertile eggs as 63.6, 67.9 and 70.3% and 92.54, 85.08, 72.93,
respectively, in their studies in which normal, rough and abnormal colored turkey
eggs were used. The differences among the groups were significant (p<0.01).
Nearly 4.5% of eggs obtained from ATAK-S parent stocks produced at Poultry
Research Institute were determined to be abnormal shaped. There are limited
studies related to the hatching characteristics of these abnormal shaped eggs.
This study was aimed to determine the economical losses arose from abnormal
eggs at hatcheries.
MATERIALS AND METHODS
The research material was 1620 eggs obtained from ATAK-S breeding layer flock
aged 60 weeks developed at Poultry research Institute. This study was done in
2009. The chemical compositions of feed materials used in the parent stocks
of study are presented in Table 1.
This study was conducted in randomized block parcels design with 6 replicates.
Parents stocks were grown in house which are windows, mechanical ventilated
and apartment-type cages. Daily lighting was 16 h. Feeding was made as ad-libitum.
Eggs were allocated to 3 groups: control, body checked shelled and rough shelled.
Eggs collected from breeding flock for 14 days were stored at 12°C and relative
humidity of 80%. Trays were taken as replicates and 90 eggs were put in each
tray. Egg trays were randomly allocated to hatchery trolley. Eggs were exposed
to preheating in a chamber (24°C and 75% relative humidity) for 8 h and
then were put into the incubator.
||Hatchability: (Alive hatched chick numbers/Placed eggs
into hatching machine)x100
||Hatchability of fertile eggs: (Alive hatched chick numbers/Placed
fertile eggs into hatching machine)x100
||Fertility: (Fertile eggs/Placed eggs into hatching machine)x100
||Early embryonic mortality: (Dead embryos during the period of 0-6
days of hatching/Fertile eggs)x100
||Mid period embryonic mortality: (Dead embryos during the period
of 7-18 days of hatching/Fertile eggs)x100
||Late period (under shell) embryonic mortality: (Dead embryos during
the period of 19-21 days of hatching/Fertile eggs)x100
||Discard chick ratio: (Placed eggs into hatching machine/Discard
||Chemical compositions of feed materials fed to parent stocks
in the study
Data were assessed by using Minitab 14 and MSTAT pocket programmes. Differences
among means were determined using variance analysis (Düzgüneş
et al., 1987). Significant differences among means were declared
by using Duncan (1955) multiple comparison test.
RESULTS AND DISCUSSION
The findings found in the present study are given in Table 2.
Fertility was not different between the groups (p>0.05). Nonexistence of
difference among the groups in terms of fertility indicates that egg shape has
no influence on fertility. Fertility occurs in infundibulum and the shape of
the egg is determined in uterus. For this reason, existence of difference in
fertility is evaluated as an expected case.
There were significant differences among the groups in terms of hatchability,
hatchability of fertile eggs, mid and late period embryo mortality (p<0.01).
Hatchability was found as 79% for normal shaped hatching eggs (control group)
with respect to the age of breeding flock. This ratio was 85-90% for young flocks.
Egg abnormalities (body checked and rough eggs) negatively affect the hatchability
and hatching characteristics. Also, hatchability of fertile eggs, early, mid
and late period embryo mortality are affected negatively by egg abnormalities.
Higher hatchability and hatchability of fertile eggs and lower late period
embryo ratio were found in normal shaped eggs compared to the other groups.
Mid period embryo mortality were found higher in rough eggs compared to those
found in other groups (p<0.01).
Early and mid period embryo mortality were found higher in rough eggs compared
to those found in other groups (p<0.01).
Discard chick ratios were found significantly different among the groups (p<0.05).
Rough egg group had higher early period embryo mortality compared to other groups
There were 0.019 and 0.370 % ratios of discard chick in rough group and body
checked group, respectively. Body checked egg group had higher discard chick
ratio compared to the other groups (p<0.05).
Roughness seems to increase the early and mid period mortality. This is in
consistence with findings of Mroz et al. (2007).
Higher early and mid period mortality in rough and body checked eggs might be
attributed to the facts that the rough and body checked eggs have thicker shell
and lower Haugh unit compared to normal eggs. Another reason is the accumulation
of excess Ca on the shell which affects respiration negatively.
||Hatching characteristics of normal and abnormal shaped eggs
and discard chick ratios
|Data is expressed as Mean±SE. Values with different
letter(s) are significantly different
Abnormal shaped eggs are obtained from breeding flocks. Ratio of abnormal shaped
eggs differs among the flocks and leads to economical losses. This study indicates
that it is possible to obtain chicks from abnormal shaped eggs and thus economical
losses can be reduced to some extent.