Effect of house type on growth performance, litter quality and incidence of foot lesions in broiler chickens reared in varying stocking density
DANIAL FARHADI, SEYED MAJID HOSSEINI, BAHAREH TAHERI DEZFULI
To evaluate the effect of different stocking density on broiler performance two repeated experiments were conducted in a conventional and an environmentally controlled house using a total of 10,232 broiler chickens. In each experiment, a total of 5,116 one-day old Ross 308 broiler chickens were randomly distributed to 16 floor pens arranged within each house at density of 16, 18, 20 or 22 birds/m2. Results showed that the broiler chickens grown in environmentally controlled house had greater (p<0.05) weight gain, kg body weight (BW)/m2, production efficiency index (PEI) and spleen relative weight at day 42 and also had lower (p<0.05) feed conversion ratio and mortality rate during 21 to 42 and 1 to 42 days of age than those reared in conventional house. Weight gain, feed intake and PEI decreased (p<0.05) and kg BW/m2 and carcass yield increased (p<0.05), when broiler density increased more than 20 birds/m2. House type and stocking density had no effect on relative weights of liver, abdominal fat, bursa of Fabricius, and litter pH and ammonia emission. However, higher litter moisture in conventional house led to a greater (p<0.05) incidence of foot pad lesions and hock burns, which intensified with increased density. In conclusion, broiler chickens reared in environmentally controlled house had superior performance, higher liability, and lower litter moisture content and foot lesions. Moreover, broiler rearing at the density of 22 birds/m2 adversely affected growth performance and foot quality, despite the greater kg BW/m2 compared to broilers grown at lower densities.
Key words: density, environment, house, performance, broiler chicken