• Korean Journal of Poultry Science
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• v.45 no.3
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• pp.155-165
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• 2018

Chicken feathers could be classified into early-feathering (EF) and late-feathering (LF) depending on the development and patterns of the wing and tail feathers. Currently, feather-sexing is a widely used chick sexing method in the industry. This study was carried out to suggest the method of classifying of EF and LF chicks to establish auto-sexing Korean native chicken (KNC) strains. The development and morphology of wing feathers and tail feathers in 856 KNCs from hatching to 55-days old were analyzed to classify EF and LF chicks. We also performed PCR analysis using K-specific gene primers to confirm the agreement between the phenotypes and genotypes of EF and LF chickens. In the results, the EF chicks had long primaries and coverts, and there was a significant difference in length between primaries and coverts. The LF chicks had shorter primaries and coverts than the EF chicks, and showed little difference in the length between primaries and coverts. LF chicks could be classified into four groups: LF-Less, LF-Scant, LF-Equal and LF-Reverse according to their wing feather patterns. EF chicks had 1.5 times longer primaries than LF chicks until they were 15-days old, but the lengths were almost the same at 50-days old. The tail feathers of the EF chicks were apparent at 5-days old, but those of the LF chicks were short and indefinite at that time. When EF and LF chicks were classified by the length of primaries being more or less than 9 mm, the classification accuracies for EF and LF chicks were 96.2% and 85.4%, respectively, compared to the PCR results. In conclusion, juvenile EF and LF KNC showed distinct differences in feather development and morphology, and could be easily distinguished at one day-old.

• Korean Journal of Poultry Science
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• v.46 no.4
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• pp.279-286
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• 2019

Currently, feather-sexing, which is based on differences in feather development at hatching, is a widely used chick sexing method in the poultry industry. For effective chicken feather-sexing, paternal early-feathering (EF) chickens and maternal late-feathering (LF) chickens must be bred. Therefore, it is critical to identify the effect of EF and LF patterns on production traits in chickens. Thus, the purpose of this study is to analyze and compare the production performances between 522 EF and 232 LF chickens in order to establish the Korean native chicken feather-sexing lines. The results showed that the survival rate of the LF group was significantly higher than that of the EF group from hatching to 52 weeks of age (P<0.05). Body weight, however, was not significantly different between the two groups at all ages. LF and EF groups did not significantly differ in age at first egg laying. However, the hen-day and hen-housed egg production of the LF group were significantly higher than those of EF group (P<0.01). No significant differences were found between the EF and LF groups in all egg quality indicators such as egg weight, eggshell color, albumin height and Haugh unit. Because the breeding target of Korean native commercial chicken is meat-type chicken, feather-sexing strains of Korean native chicken should be established using weighing-based paternal EF lines and laying-based maternal LF lines. Therefore, these results are critical for establishing desirable and effective feather-sexing strains.

• Proceedings of the Zoological Society Korea Conference
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• 1998.10b
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• pp.237.1-237
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• 1998

• Bulletin of Korea Environmental Preservation Association
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• v.26 s.354
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• pp.46-47
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• 2004

• Proceedings of the Korean Society of Applied Entomolohy Conference
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• 2005.05a
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• pp.78-78
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• 2005

• Monthly Duck's Village
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• s.88
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• pp.48.2-48.2
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• 2010

• KOREAN POULTRY JOURNAL
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• v.43 no.4
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• pp.140-144
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• 2011

• KOREAN POULTRY JOURNAL
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• v.53 no.7
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• pp.170-175
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• 2021

• Parasites, Hosts and Diseases
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• v.32 no.2
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• pp.75-84
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• 1994

About 6,950 fEather mites were isolated from field collections and examination of bird study skins at the zoological specimen room of Kon-Kuk University in Seoul. Among them, 3 species of Kramerellidae, Dermonoton longiventer (Megnln & Trouessart, 1884), Kramerella bubonis (Lonnfors, 1937) , Neopetitotcl bubonis Atyeo & Philips, 1984, and 1 species of Pterolichidae, EpopoLichn atelw Gaud, 1981 were newly recorded from Korea. They were redescribed with their new hosts.

• The Korean Journal of Zoology
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• v.20 no.1
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• pp.29-40
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• 1977

The authors examined fresh-water gammarid materials which were collected from streams in 20 localities of South Korea during the period from 1965 to 1977. As the results of the observation, the authors have concluded as follows: 1. These fresh-water gammarids belong to Gammarus pulex-group and are distributed widely in mountain-streams of mainland and surrounding islands of South Korea. 2. The present specimens are different from the subspecies, G. pulex koreanus Ueno, 1940 which was described originally from North Korea. In the latter, the pulmose setae of third uropod are limited only to the outer margin of both rami. The peduncle and flagellum of second antenna are fringed with a few short setae and the flagellum is provided with calceoli. In the former, both margins of inner ramus and outer margin of outer ramus of third uropod are fringed with long pulmose setae. The peduncle and flagellum of second antenna have abundant relatively long setase and the flagellum is not provided with calceoli. 3. The present specimens are different from the subspecies, G. pulex sobaegensis Ueno, 1966 which was described originally from South Korea. The latter dwells in cave, while the former dwells in mountain-stream. In the former, the arrangements of pulmose setae of third uropod and the setation of second antenna are similar to those of the latter. But they are quite different from each other in several characters such as shape of upper lip, shape of fifth article of second gnathopod and numbers of incisions on front distal margins of coxal plates 1-3. The former has spines on surface of coxal plates 1-3, but the latter has not. In females, the former has four pairs of marsupial plates, while the latter has three pairs. 4. The present materials show local variations. Therefore, they could be divided into 3 local groups. The first group (specimens from Mt. Odae and Mt. Sogeumgang) has pulmose setae on the both margins of both rami of third uropod and second article of outer ramus is relatively long. In general, this group has setae sparsely on the both rami and especially a few setae on the outer margin of outer ramus. The second group, which are widely distributed in South Korea, has pulmose setae on the both margins of inner ramus and on the outer margin of outer ramus of third uropod. In the third group (specimens from Mt. Soyo), the pulmose setation of third uropod is similar to that of the first group, but the second article of outer ramus is very small.