The effect of group size on behaviour and production of broiler

Present experimental study was conducted to determine the effect of group size on behaviour and production of broiler for 6 weeks, during March- April 2002. The broilers of all groups were housed under similar managemental conditions and offered same feed. Feed intake during brooding period in groups A, B and C was 354.0, 355.0 and 364.0 g/b which was not significantly different for groups and interaction between groups and weeks; while during 3 to 6 weeks (growing period) feed intake was significantly different for groups and interactions i.e. 3.717, 3.781, 3.294, 3.246 and 3.208 kg/b for A, B, C, D and E groups, respectively. Average live body weights of broiler were increased with the progress of period, i.e. 1.858, 1.920, 1.846, 1.876 and 1.880 kg/b in groups A, B, C, D and E, respectively, but was not significantly different in groups. The data on mortality showed that 6 birds were died in 200 birds flock (Group D) as compared to 0 mortal ity in 50 birds flock (Group A). In case of social behaviours, the av. aggression instigated by broiler under A, B, C, D and E groups were 1.9, 1.3, 0.6, 0.6 and 1.2 incidences/24 hr. which was not significantly different between groups. The aggression target behaviours of broiler under group A, B, C, D and E were 2.3, 2.0, 0.5 0.9 and 1.0 incidences/br/24 hr. and difference between each group was significantly different. The aggression avoidance observed in groups A, B, C, D and E were 2.10, 1.70, 1.20, 1.40 and 2.70 incidence/b/24 hr. but no significant difference between each group. The flying behaviour of broilers in groups A, B, C, D, and E were 0.3, 0.3, 0.0, 0.1 and 0.5 incidences/b/24 hr., playing behaviour 0.6, 0.6, 0.3, 0.4 and 1.1 incidence/b/24 hr., respectively. However, the difference between the groups was not different significantly. The aggression instigator and target behaviours were 4.20, 3.30, 1.10, 1.50 and 2.20 incidences/b/24 hours, the total aggressio n behaviours (instigator+target + avoidance) 6.30, 5.00, 2.30, 2.90 and 4.90 incidences/b/24 hours and flying + playing behaviours were 0.90, 0.90, 0.30, 0.50 and 1.60 incidences/b/24 hours, in groups A, B, C, D and E, respectively. Overall behaviours were 11.40, 9.20, 3.70, 4.90 and 8.70 incidences/b/ 24 hours, respectively. Total feed consumption accumulated was 4.071, 4.135, 3.648, 3.600 and 3.572 kg/broiler, producing weight gain 1.816, 1.878, 1.804, 1.834 and 1.837 kg per broiler and corresponding FCR was 2.242, 2.202, 2.022, 1.963 and 1.944, in groups A, B, C, D and E, respectively. The total cost accumulated was Rs.69.781, 70.485, 65.128, 64.600 and 64.292 against the total income of Rs.79.894, 82.560, 79.378, 80.668 and 80.840 per broiler, in groups A, B, C, D and E, respectively. So, the net profit per broiler earned was Rs.10.113, 12.075, 14.250, 16.068 and 16.548 in groups A, B, C, D and E, respectively. The results show that overall feed intake was significantly r e duced with the increased group size with no significant change in final live body weight of broiler. Smaller group size broiler was found more under aggression targets than others. Broiler of small group sizes involved more in total aggression behaviours and also in total social activities. Those broilers of small group sizes consumed larger quantities of feed to become more expensive. Larger group sizes broiler were better converter of feed into meat (FCR) than other small group sizes and become more economical for farmers.