• Korean Journal of Poultry Science
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• v.51 no.2
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• pp.83-95
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• 2024

This study aimed to assess the performance of laying hens across twelve crossbreed strains (i.e., CFCK, CFYC, CFYD, CKCF, CKYC, CKYD, YCYD, YCCF, YCCK, YDCF, YDCK, and YDYC) of Korean native chicken (KNC) and compare them with Hy-Line Brown layers. A total of 287 18-week-old laying hens were placed in battery cages by strains (2-5 birds per pen). Results indicated that the YCYD and YDYC strains exhibited numerically heavier body weights than Hy-Line Brown at week 18-64. CKYC and YDYC strains demonstrated more than 94% viability by week 64. The CFYC strain had an age of first egg laying of 127 days, and the YDCF strain reached an age of 50% egg production at 140 days, both earlier than their parent stock. The YDCF strain showed over 70% egg production for up to 60 weeks. Regarding egg quality, the CKCF and YCCF strains had numerically higher egg weights among the KNC groups at week 24-64, with the YDYC strain showing a darker (P<0.05) eggshell color compared to CKCF at week 40. Moreover, KNC crossbreeds showed a higher (P<0.05) egg yolk ratio than Hy-Line Brown. In conclusion, the YDCF and YCCF crossbreeds exhibited the most desirable new synthetic Korean native commercial layer based on egg production and quality parameters. Therefore, these strains could be a viable substitute for Hy-Line Brown layers.

• Korean Journal of Poultry Science
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• v.50 no.4
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• pp.203-212
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• 2023

This study conducted a diallel-crossbreeding test using four Korean native chicken parent stock lines (YC, YD, CK, and CF) to develop a native commercial layer with high egg-laying performance. A total of 312 chickens in six combinations were examined for various traits, including livability, body weight, age at first egg-laying, hen-day, and hen-housed egg production, egg weight, and egg quality, from hatching to 60 weeks of age. The results showed that the average survival rate was 77.1±18.8% with the YDYC combination having the highest survival rate along with excellent specific combining ability. The YDYC combination exhibited significantly higher body weight compared to the other combinations (P<0.01). The average age at first egg-laying was 121.3±2.5 days, with no significant difference between the combinations. The average hen-day egg production was 74.0±6.4%, and the hen-housed egg production was 181.4±33.8 eggs with the YDCF and YCCK combinations demonstrating the highest laying performance, while the YDYC and CKCF combinations had the lowest (P<0.05). Laying performance was more influenced by specific combining ability than general combining ability. The eggs from the YDYC combination were significantly lighter and had the darkest shell color (P<0.01), whereas the YDCF combination exhibited the thickest eggshells. There was no difference in internal egg quality among combinations, except the YDCF combination had the darkest yolk color. Overall, we concluded that the YCCK combination, characterized by high laying performance and livability, and the YDCF combination with high laying performance and good egg quality are the most desirable combinations for Korean native commercial layers.

• Korean Journal of Poultry Science
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• v.50 no.4
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• pp.303-310
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• 2023

The current study was conducted to compare the effect of crossbred on the body weight and laying performance of Korean native chicken from hatch to week 40. A total of 873 one-day-old chicks were divided into twelve crossbreds (i.e., CFCK, CFYC, CFYD, CKCF, CKYC, CKYD, YCYD, YCCF, YCCK, YDCF, YDCK, and YDYC) and commercial layer (Hy-Line Brown) were obtained as a counterpart in the study. All the birds are raised in battery cages (76 × 61 × 46 cm³) and then raised until 14 weeks and subsequently moved to layer battery cages (60 × 25 × 45 cm³) and raised until 16 weeks. The body weight and viability were measured biweekly from hatching to week 16. The week of 16, body weight range was about 1,010.24 to 1,411.77 g. The body weight of specific crossbreeds (i.e., CKCF, YCYD, and YDYC) was found to be comparable to that of Hy-Line Brown). The viability hatch to week 14 range was about 55 to 100% and however week 14 to 16 range was 80 to 100%. The crossbred (i.e., CKCF) recorded superior (P<0.05) viability throughout the whole experiment period, even compared with Hy-Line Brown (100% vs 96%). Our results are indicating that crossbreds Korean native chicken including CKCF, and YDYC has the potential to enhance key features of laying hens during the growing phase like optimal body weight and higher viability.

• Korean Journal of Poultry Science
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• v.38 no.4
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• pp.331-338
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• 2011

The study was conducted to evaluate the production and the performance test of egg-type commercial Korean Native Chickens. A total of 360 female layers were produced from CY${\times}$C (A), CL${\times}$C (B), CG${\times}$C (C) and CW${\times}$C (D) crossbreds kept at National Institute of Animal Science, Korea, and breed during 20~64 weeks to investigate the productivity and the performance. Layers were divided into 4 crossbreds (6 replications/crossbred, 15 heads/replication). Age and egg weight at first egg was no significantly different among crossbreds. Body weight (BW) at first egg of D crossbred was significantly lower compared to that of other crossbreds (P<0.05). Weekly BW of B crossbred was the highest at 20, 30 and 40 weeks of age, but BW of D crossbred was the lowest among crossbreds. Feed intake (FI) of B crossbred was significantly higher compared to the other crossbreds at 20~24, 32~44 and 52~60 weeks of age. FI of D crossbred was significantly lower compared to other crossbreds after the age of 44 weeks (P<0.05). Average egg weight of B crossbred was significantly higher than the other crossbreds at the age of 24~60 weeks (P<0.05). Egg production ratio (%) of C crossbred was significantly higher compared to the other crossbreds for whole test periods (P<0.05). Hen-housed egg production number at 64 weeks of age for A, B, C and D crossbreds resulted in 241.4, 235.6, 232.3 and 227.0, respectively. Feed conversion ratio of A and C crossbreds was lower compared to the other crossbreds at the age of 20~24 weeks and C crossbred was the lowest among the crossbreds at the age of 60~64 weeks. These results provide the basic data which will be helpful to develope the new strains of commercial Korean Native Chickens.

• Korean Journal of Poultry Science
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• v.39 no.3
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• pp.245-252
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• 2012

This study was carried out to investigate the performance of laying period of two-crossbred of Korean native chickens for producing laying hens. A total of four hundred eighty female 2-crossbred chicks that restored strains and were aboriginal at National Institute of Animal Science. There were four crossbreds (4 replications/crossbred, 30 birds/replication) as A) C strain ${\times}$ Y strain, B) C strain ${\times}$ L strain, C) C strain ${\times}$ G strain, and D) C strain ${\times}$ W strain, respectively. There were no significant difference on age at first egg among crossbreds (P>0.05). Egg weight and body weight of B crossbred at first egg was higher than other crossbreds (P<0.05). Body weight of B crossbred was the highest 20 to 72 weeks (P<0.05), and C and D crossbreds were lower compared to A and B crossbreds (P<0.05). Average feed intake of B crossbred was the highest among crossbreds (P<0.05), and that of A crossbred was higher compared to C and D crossbreds (P<0.05). Weekly feed intake of four crossbreds decreased from 50 weeks. Weekly egg weight of B crossbred was the highest and that of D crossbred was the lowest among crossbreds (P<0.05). Feed conversion ratio of A and B crossbreds was lower than that of C and D crossbreds. Hen-house egg production of C crossbred was the highest among crossbreds until 26 weeks old (P<0.05), but there was no significant difference among crossbreds from at the age of 26 weeks (P>0.05). Hen-day egg production decreased after at the age of 38 weeks. Weekly egg production of A and B crossbreds was higher compared to C and D crossbreds at the age of 68~72 weeks (P<0.05). These results suggested the basic data on the record of laying period of 2-crossbreed Korean Native Chickens for producing laying hens.

• Korean Journal of Poultry Science
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• v.39 no.2
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• pp.133-141
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• 2012

This study was carried out to investigate the performance of laying period of two-way crossbred of Korean native chickens. A total of four hundred eighty female 2-crossbred chicks that restored strains and were aboriginal at National Institute of Animal Science. Treatments were four crossbreds (4 replications/crossbred, 30 birds/replication) as A) C strain ${\times}$ S strain, B) C strain ${\times}$ H strain, C) R strain ${\times}$ S strain, and D) L strain ${\times}$ H strain, respectively. There were no significant difference on age, egg weight, and body weight at first egg among crossbreds (P>0.05). Body weight of D crossbred was lower compared to other crossbreds at the age of 24, 32, 40 and 60 week (P<0.05). Feed intake of A crossbred was highest among crossbreds (P<0.05). Weekly egg weight of A crossbred was the highest among crossbreds all laying period except 48~52 and 60~64 weeks. Hen-house egg production of A and B crossbreds was higher than that of C and D crossbreds (P<0.05). Hen-day egg production decreased after at the age of 36 weeks. Weekly egg production of A and B crossbreds was higher compared to C and D crossbreds (P<0.05). These results suggested the basic data on the record of laying period of 2-crossbreed Korean Native Chickens.

• Korean Journal of Poultry Science
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• v.39 no.3
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• pp.177-182
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• 2012

This work was carried out to investigate the performance of growing period of two-way crossed of Korean native chickens parental stocks. A total of four hundred eighty female 2-crossbred chicks were used in this study and they were from National Institute of Animal Science. Groups were four crossbreds (4 replications/crossbred, 30 birds/replication) as A) C strain ${\times}$ Y strain, B) C strain ${\times}$ L strain, C) C strain ${\times}$ G strain and D) C strain ${\times}$ W strain. Body weight of A crossbred was the highest at the age of 8 week (P<0.05) and that of D strain was the lowest for growing period (P<0.05). Body weights of A and B crossbreds were higher than those of C and D crossbreds at the 12 and 16 weeks (P<0.05). Weekly body weights of A and B crossbreds were higher than C and D crossbreds (P<0.05), and weekly body weight of B crossbred was higher compared to other crossbreds at 0~20 weeks old. Weekly feed intake of D crossbred was the lowest among all crossbreds at 0~12, 0~16 and 0~20 weeks old (P<0.05). Weekly feed conversion ratio of C crossbred was the highest among crossbreds (P<0.05). These results can give the basic information for growth related data in 2-way crossbreed Korean Native Chickens, which can be used for the parental stocks for the laying-type of Korean native commercial chickens.

• Korean Journal of Poultry Science
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• v.44 no.3
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• pp.189-198
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• 2017

This study was conducted to develop a new synthetic breed of Korean native chicken. The combining ability and reciprocal effects for production traits were estimated on 1,157 hens from a $5{\times}5$ diallel cross-mating design using grand parent stock (GPS) lines of Korean native chicken. Body weight, viability, age at first egg laying, egg weight, and hen-day egg production were measured and analyzed. The results showed that the general combining ability (GCA) of the survival rate during laying periods was -9.6 to 11.1, with the highest value obtained in the W strain. Additionally, the GCA of the body weight at 12 weeks was -209.7 to 162.2, with the highest value obtained in the F strain. The GCA for age at fist egg laying was estimated to be -2.8 to 3.7, while the GCA of egg weight was -0.91 to 0.96, and the GCA of hen-day egg production was -4.9 to 6.0. In the estimation of specific combining ability, the YW combination showed the highest survival rate, FW showed the highest body weight at 12 weeks, and GW showed the highest hen-day egg production. The reciprocal effects were significantly different among crosses for almost all productivity traits. In identical breeding combinations, differences in ability were observed when the maternal or paternal breeds were switched. The mean value based on combining ability was higher in WY, WF, and GW combinations for survival rate; GF, HG, and HF combinations for body weight at 12 weeks; and GW, YW, and FW combinations for hen-day egg production. It is concluded that the GF and HF combinations, which have excellent growth performance and moderate survival rate, are the most desirable paternal parent stock (PS) strains, and the GW and FW combinations, which have great laying performance and moderate body weight, are the most desirable maternal PS strains.

• Korean Journal of Poultry Science
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• v.44 no.2
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• pp.123-134
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• 2017

This study was conducted to establish new synthetic lines of Korean Native Chicken. We performed $5{\times}5$ diallel crossings with GPS lines of Korean Native Chicken for the selection of parent stock. The production traits including viability, body weight, age at first egg laying, egg weight, hen-day egg production, and hen-housed egg production were measured and analyzed for 25 crosses with 1,157 hens. The heterosis effects of these traits were also estimated. The results showed that the average survival rate during laying periods was 67.7% in the pure lines and 77.1% in the crosses. The 25 cross combinations were shown to be distinctly divided into three groups according to body weight; nine crosses in the high-weight group, 12 crosses in the medium-weight group and four crosses in the light-weight group. The average body weight at 12 weeks of age was $1,873.8{\pm}43.0g$ in the high group, $1,595.4{\pm}56.6g$ in the medium group and $1,152.7{\pm}24.7g$ in the light group, and $1,560.2{\pm}339.3g$ in the pure lines and $1,640.9{\pm}213.7g$ in the crosses. In terms of egg production performance, the age at first egg laying was $139.7{\pm}4.9$ days in the pure lines and $135.8{\pm}5.1$ days in the crosses. The average egg weight was $52.3{\pm}1.6g$ in the pure line and $53.0{\pm}1.6g$ in the crosses. The average hen-housed egg production from 20 to 40 weeks was $58.3{\pm}12.9$ eggs in the pure line and $69.2{\pm}10.4$ eggs in the crosses. The average heterosis effect was 16.9% for survival rate, 5.4% for body weight at 12 weeks, -2.7% for age at first egg laying, 1.3% for egg weight, and 14.3% for hen-day egg production. Generally, the heterosis effect for viability and egg production traits was higher than that for growth trait. On the basis of these results, it is expected that the selection of the HF combination, which had excellent growth performance, is the most desirable as the paternal strain, and the selection of GW and FW combinations, which had excellent laying performance, are preferable as the maternal strain.

• Korean Journal of Poultry Science
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• v.40 no.4
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• pp.291-297
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• 2013

This study was conducted to evaluate the productivity of Korean native chicken (KNC) 2 strains crossbred. The number of chicks analyzed in this study was 300. Crossbreds used in this studywere A) KNC R strains ${\times}$ KNC meat type S strains, B) KNC egg-meat D strains ${\times}$ KNC meat type H strains, C) KNC egg-meat D strains ${\times}$ KNC meat type S strains, D) KNC egg-meat C strains ${\times}$ KNC native Y strains, and E) KNC native Y strains ${\times}$ KNC meat type H strains. The crossbreds C had the highest performance on body weight gains at 7~10 weeks but crossbreds D showed the lowest (p<0.05). The feed conversion ratio of crossbreds D was the highest value at every weeks (p<0.05). But the carcass weight and carcass ratio of crossbreds D was the lowest value at every weeks (p<0.05). For the percentage of cutted meat, the ranges of mean were 30.60~33.75% in breast, 21.48~24.72% in leg, 11.95~14.33% in wing, 21.91~25.83% in back and of 7.38~8.72% in neck. The percentage of cutted meat for leg was the highest value at every weeks (p<0.05). These results suggested that the development of new crossbreds should be necessary for better performance.