The invention relates to a chicken HS6ST3 
gene 43bp 
indel polymorphic marker, application thereof, a detection primer and a 
reagent kit, and belongs to the technical field of molecular genetic breeding. The chicken HS6ST3 
gene 43bp 
indel polymorphic marker, the application, the detection primer and the 
reagent kit have the advantages that the 43bp 
indel polymorphic marker in first introns of HS6ST3 genes is discovered, is obviously related to diversified economic characters such as 12-week shank circumferences and 6-week body weights of chicken and can be used for assisted selection and 
molecular breeding on the chicken; particularly, an amplification fragment designed according to a sequence shown as SEQ ID NO.1 contains the primer at 176th-218th bits from a 5' end of the sequence, whether the 176th-218th bits are inserted / deleted can be judged according to the sizes of amplification products, breeding on dominant 
genotype individuals with 176th-218th bit homozygous deletion can be reinforced, accordingly, the 
economic benefits of indigenous and commercial chicken can be increased, methods are free of 
enzyme digestion, accurate in 
genotype judgment, easy to operate, low in cost and short in period, and discrimination can be facilitated.