Age and Cage Tiers: Effects on productive performance, blood profile and egg quality traits of egg-type chickens

Abstract

Age of birds is critical for laying performance and egg quality traits of birds; however, the effect of cage tiers in laying performance is rarely investigated. This study determined the effects of age and cage tier on laying performance and egg quality traits of Isa Brown® chickens. A total of 576 birds of commercial layers (Isa Brown®) of average body weight 1.4 kg were used for the experiment. They were housed in three-tier conventional battery cages (top, middle and bottom) with spacing of 610 cm2/bird. The experiment was conducted on Isa Brown® chickens from the age of 21-30 weeks, 31- 40 weeks and 41-50 weeks. Birds were randomly distributed into 9 treatments, consisting of 4 replicates and 16 birds per replicate. Data were collected on the average weight gain (AWG), feed intake, net feed efficiency index (NFEI), hen-day egg production (HEDP) and feed per dozen eggs, blood parameters (haematological and serum biochemical indices) and egg quality traits (external and internal). The experiment was laid out in a 3×3 factorial arrangement and data collected were subjected to two-way Analysis of Variance in a Completely Randomised Design. Results showed significant variations (p<0.05) in the AWG, HDEP and NFEI from ages 21-30, 31- 40 and 41-50 weeks in birds housed at top-tier, respectively. The interaction effects between age and cage tier significantly (p<0.05) influenced total protein and globulin across the ages with highest values (5.55 g/dl and 2.15 g/dl) between ages 41-50 weeks and 21-30 weeks, respectively in birds housed on top-tier. Interaction effects between age and cage tier on external and internal egg quality traits showed significant influence (p<0.05) on the egg weight and yolk weight across the treatments. Birds within ages 31- 40 weeks had the highest (p<0.05) egg weight (68.30 g) in birds kept at mid-tier and yolk weight within ages 31- 40 weeks (16.65 g) at top-tier. The study concluded that egg production was better within ages 21- 30 and 31- 40 weeks on top-tier while external and internal quality traits of eggs are best within ages 31 - 40 weeks in birds kept in mid-tier and top-tier. However, any of the cage tiers is applicable in maintaining the serum biochemical parameters of the Isa Brown® chickens.