Sex determination was an unknown process in hatchery until 1925. Later, different
methods, such as biochemical, histological, auto sexing, watching cloak and
other instruments have been used to differentiate female and male chicks (Goger
and Durmus, 2005). In auto sexing, wing feather colour and the speed of
feathering at wing are criteria for sex determination (Wilson
et al., 2007).
In day old chicks, the speed of wing and tail feathering is determined by the
genes K and k alleles which are located in Z sex chromosomes as informed firstly
by Waren (Aksoy et al., 2002).
Sex determination based on slow and rapid feathering in egg layer chicks is
widely used in poultry breeder farms in USA. In this method, the length of primer
and secondary feathers at wing is measured. If slow feathering hens are husbandired
with rapid feathering cocks, female hatchlings are rapid feathered while males
are slow feathered. However, chicks having slow feathering gene show late sexual
maturity and reduction in egg production and need a higher amount of dietary
energy (Wilson et al., 2007).
Saleh et al. (1987) found that axe combed white
rapid feathering Leghorns reached to sexual maturity earlier and produced more
eggs compared to slow feathering Leghorns.
Dunninngton and Siegel (1986) determined that the effects
of rapid and slow feathering alleles on first egg age and egg yield were not
different between rapid and slow feathering groups.
Bacon et al. (1986) reported that there was
no relationship between slow feathering and immunity. Fotsa
et al. (2001) found out that slow (K gene) and rapid (k+
gene) feathering in leghorn and brown layers in different ambient temperatures
did not affect weight gain and fattening. White Rock chickens showing rapid
and slow feathering were not different from each other with respect to feed
conversion ratio and growth traits while mortality rates were higher in slow
feathering chickens (15%) than in rapid feathering (6%) ones (Thiagarajon,
1977). Lowe and Garwood (1981) reported that feathering
genotype did not affect hen-day egg production, body weight and egg weight in
Rhode Island Red and White leghorn hybrids. Dunninngton
et al. (1986) demonstrated that chicks having k gene (K) were more
sensitive to E. coli infection.
Khosravinia (2009), who worked with broilers allowing
sex determination based on slow and rapid feathering, reported that live weight
and carcass weights of rapid feathering broilers were significantly higher than
those of slow feathering ones.
Low and rapid feathering strains were obtained from brown layers Line-54 at
the Poultry Research Institute in Turkey. This study aimed at investigating
the effects of the speed of feathering on some production and hatchability traits
in these two strains.
MATERIALS AND METHODS
This study was carried out at the Poultry Research Institute in Turkey date
of between 01 June, 2004 and 20 September, 2008. Animal material was composed
of rapid and slow feathering strains produced from Line-54 pure lines according
to the wing feathering speed. Feed material was composed of feeds, whose nutrient
compositions is shown in Table 1.
The available brown layer has a feathering gene frequency of L-54 pure line
that is 55% rapid and 45% slow. Considering this feature, 1800 eggs obtained
from this line were incubated. On the first day, the chicks were divided into
two groups: the ones feathering slowly and the ones feathering rapid without
looking at their sex. Later, the chicks underwent a sex separation system and
250 female chicks and 40 male chicks from each group were selected.
||Chemical compositions of feed materials fed to hens in the
A total of 500 female chicks and 80 male chicks were collected and numbered.
When the chicks reached their 10th day, their tail feathers were checked. After
chicks were reared, the productivity of the eggs was noted and the ones with
a lower capacity were separated until the chicks reached their 43rd week. Forty
families were established from each group consisting of 5 hens and 1 cock. The
hens were artificially inseminated and the eggs obtained were incubated. The
chicks obtained were checked due to their family based feathering and the ones,
which showed some differences, were separated. The process, which was applied
to the first generation, was again applied to this generation. When the chickens
reached the 43 week egg productivity, a homozygote test was applied to the ones
whose feathers grew slowly and the ones that had the heterozygote (Kk) gene
type were separated. After these processes, similar families were established
and the same process for the second generation was applied to the third generation.
In this generation looking at the L-54 pure line looking the feathering condition
formed again the two strains.
In this study, at a total of 250 hens and 50 cocks coming from every strain
formed of 125 hens and 25 cocks were obtained with the process mentioned above.
Hatching eggs produced from the hens obtained with this method were put in
incubation and chickens were raised for 16 weeks following hatching and then
were transported to the cages. Hens were exposed to natural daylight during
the growing period and from the 19th week lighting time was increased by 1 h
for each week and finally was fixed at 16 h. Feed and water were given ad
From the beginning of laying period to the end of 43rd week age
||Sexual maturity (day): For both lines were determined
by taking the duration between hatching date and beginning of egg yielding
||Sexual maturity weight: Sexual maturity weights for both lines
were determined by weighing the hens with a scale of 5.0 g sensitivity at
the beginning of egg production
||Egg production: Hen-day egg yields for both lines were determined
by determining the egg counts during the production period up to the 43
||Egg weight: Average egg weights were determined by weighing two
successive eggs for every 4 weeks from the beginning of 28th week in each
||Egg mass: Egg mass was calculated by multiplying total egg counts
by average egg weights in each line separately
After having obtained production records at 43 weeks old, flocks having either
slow and rapid feathered were kept 1 cock +5 hens with 25 replications. The
hens were inseminated artificially with their cocks in their family twice a
week. After the second insemination, eggs were collected for 10 days and stored
in a room having 12°C ambient temperature with 80% relative humidity. After
the collection of the eggs, they were subjected to pre-heating with 23°C
ambient temperature and 75% relative humidity for 8 h in prior to hatching.
After optimum hatching conditions were reached, eggs were detected by lamp for
fertility, by cracking eggs for determining early and middle period embryonic
mortality at 18 days of hatching and transferred from developer to hatcher.
Infertile and dead embryos were discarded and healthy ones were transferred
to hatcher with pedigree boxes. After 21 days of hatching period, healthy chicks
and late embryonic mortalities were determined.
This study was conducted according to the randomized block experimental
design and data were tested for distribution normality and homogeneity of variance.
One way ANOVA was used to determine the differences each traits. Data in percentages
were subjected to arcsin transformation ()
(Duzgunes et al., 1987).
Hen-day egg production, egg weight, sexual maturity and live weight at sexual
maturity were affected by slow and rapid feathering genotype (p<0.01), but
egg mass was not (p>0.05). Rapid feathering hens were better than slow ones
with respect to production parameters, except for egg weight and egg mass (Table
With respect to current hatchability and middle period embryonic mortalities,
there were no significant differences between rapid and slow feathering chickens
(p>0.05). Fertility (p<0.05), early embryonic mortality and hatchability
of fertile eggs (p<0.01) were affected significantly by slow and rapid feathering
genotypes. Hatchability and middle period embryonic mortalities were similar
in both groups. However, fertility, early and late embryonic mortalities and
hatchability parameters were higher in rapid feathering group than slow feathering
group (Table 3).
||Means±SE of some productive traits of rapid and slow
feathering layer genotypes
|a, b: p<0.01
||Means±SE of some hatching parameters of rapid and slow
feathering layer genotypes
|a, b: *p<0.05, **p<0.01
With respect to sexual maturity, slow feathering pullets reached sexual maturity
5 days later than did the rapid feathering pullets. This affected egg production
negatively in this study. However, it was expected that hens would compensate
the reduction in egg production when experiment would have continued further.
While the present findings are in agreement with those of Wilson
et al. (2007) and Saleh et al. (1987)
they are in disagreement with those of Lowe and Garwood
(1981) and Dunninngton and Siegel (1986).
Hen-day egg production and body weight at sexual maturity were better in the
rapid feathering group than the slow feathering group. Low body weight at sexual
maturity in the rapid feathering group can be advantageous for feed consumption.
Although, egg weight was higher in the slow feathering group, egg production
was lower. This led to similar egg mass values in both feathering groups.
Early and late embryonic mortality in rapid feathering genotype was lower than
in slow feathering chickens as evidenced by higher hatchability in the former
group. This was reflected to a higher hatchability in rapid feathering eggs.
Also, lower early and late period embryonic mortalities helped this positive
result for rapid feathering hens. Hatchability was not affected by slow and
rapid feathering. Insignificant differences in obtained parameters were more
likely because of chance.
In breeder enterprises, sex determination is a very important subject. Although,
sex determination is done with different methods, especially wing feathering
is quite widespread in the parent stock enterprises. As shown in current findings,
some productive traits started to decline in slow feathered genotypes when slow
and rapid feathered chicken breeders were bred separately. However, there were
differences in production parameters, these differences were not reflected in
egg mass, which is regarded as the total value of production parameters. The
egg mass values of both feathering groups were found similar (Table
Hatchability is a result of hatching in hatchery. Hatchability must not be
below 89% for commercial hatchery. This value varies depending on parent stock,
grand parent stock and pure breeds for their hatchery results. In the current
study, rapid and slow feathering flocks which were obtained by selection showed
With respect to hatching traits, there were significant differences between
slow and feathering chickens but hatchability was not affected by slow and rapid
This study was supported by the Poultry Research Institute in Turkey.