Effects of stocking density and genetic group on broilers performance and bone development

Abstract

The aim of this study was to evaluate the effects of stocking density (10 and 16 birds/m²) and of genetic group (Hybro PG, Isa Label JA57 and Ross 308) on performance, carcass yield and bone development in broiler chickens. A completely randomized design was used, in a 3x2 factorial factorial arrangement (3 genetic groups x 2 stocking densities). Tibia, femur and humerus samples were collected when chickens were 1, 7, 14, 21, 28, 35 and 42 days old. The evaluated parameters were length and width (mm, expressed in absolute values), dry bone weight (g) and Seedor index (dry bone weight divided by bone length, mg/mm). No difference between the genetic groups and the stocking densities was found for most of the parameters evaluated, except for humerus width of the genetic groups Ross 308 and Hybro PG reared at the densities of 10 and 16 birds/m². Interactions between density and genetic group were not found for animal performance and carcass yield. All variables were increased with chicken age. Small differences were observed in bone development patterns of the genetic groups Ross 308 and Hybro PG