The Size and Shape of IPB Chickens and Kampong Chickens in Relation to Natural Selection

Abstract

IPB D1 chickens have been shown to exhibit superior growth and reproductive performance in comparison to kampong chickens, as demonstrated in previous studies. The selection of IPB D1 chickens
resulted in the generation of IPB D2 and IPB D3 chickens. The objective of this study is to make a
comparative analysis of the size and body shape of kampong chickens, IPB D1 chickens, IPB D2 chickens,
and IPB D3 chickens. This analysis will be based on crowd diagrams during the starter and grower
periods. The present study employed Principal Component Analysis (PCA) based on measurements of
eight linear body surface area variables, including femur length, tibia length, tarsometatarsus length,
tarsometatarsus circumference, third toe length, wing length, maxilla length, and comb height. These
variables are closely related to adaptive ability, resulting from natural selection. The selection of chickens
based on eight linear body surface area, in conjunction with natural selection, has been demonstrated
to enhance chicken productivity. The analysis results demonstrate that IPB D1 and IPB D2 cocks, and
IPB D2 and IPB D3 hens, in the starter period exhibit comparable body shapes, suggesting a relatively
uniform morphological pattern resulting from shared direction of selection. During the grower period,
disparities in the direction of selection became evident between IPB D2 and IPB D3 cocks, as evidenced
by the distribution of individual points in divergent directions in the cluster diagram. This phenomenon
is indicative of disparities in selection pressure on body characteristics in the two strains. Significantly,
during the starter period, a separate group of kampong hens formed at the top of the diagram, indicating the strong uniqueness of native chicken morphological characteristics and a body size pattern that is strikingly different from the IPB selection strain.