Comparative analysis of the phenotypic variability of chickens of different productivity directions

In poultry, chicken exterior evaluation is necessary to determine the compliance of chickens with breed standards, productivity direction and to asses genetic diversity. The object of the study were hens of Tsarskoye Selo (Ts), Pushkin (Pus), Russian White (RW), Novopavlovo gold (NG), Cochin Dwarf (CD) and Silky (S) breeds. Long-leggedness index (LLI) and eurisomy index (EI) were calculated based on body measurements. Our studies showed that chickens of different productivity directions vary in values of live weight, linear body measurements and the degree of expression of their relationships. Dual-purpose breeds were characterized by the greatest leg length. The lowest LLI was observed in CCs (49.2%), and they appeared to have the widest and thickest constitution according to EI. The CD surpassed PG by 24.5%, S by 24.4%, and RW by 12.2% on this index. A greater number of reliable correlations between body measurements was obtained for RW hens, which indirectly indicates a high potential of egg productivity in this breed. Fancy chicken breeds showed a smaller number of reliable correlations, and the traits “chest girth”, “metatarsus girth” had a weak correlation in contrast to productive breeds. The greatest number of positive correlations was obtained for CD. The results of cluster analysis indicate that chickens of different productivity exhibit specific exterior traits, which can be modeled by analyzing body measurement data.