Effect of feed particle size on the performance of broiler chickens in peak summer

An experiment was conducted to evaluate the effect of feed particle size on the performance of broiler chicks up to 42 d age. 160, day old broiler chicks divided randomly in to 4 equal groups were offered isonitrogenous and isocaloric diets ground to pass through either 2, 3, 4 or 6 mm screen size using a hammer mill and designated as PS₂, PS₃, PS₄ and PS₆, respectively. The average minimum and maximum temperature in the shed was 26.5 and 38.0° C, respectively. The average particle size increased (P<0.05) whereas the surface area decreased linearly (P<0.05) with the increase in pore size of screen. A smaller geometric standard deviation in PS₂ represented a higher (P<0.05) particle size uniformity. The feed intake in PS₂ was lower (P<0.05) than PS₃, PS₄and PS₆ The weights attained increased (P<0.05) from 689 g in PS₂ to 1018 g in PS₆ at 42 d of age. The feed efficiency also improved with the increase in the particle size and was better (P<0.05) in PS₆ (2.1) than in PS₂ (2.6) PS₃ (2.4) and PS₄ (2.4). Against a financial loss of 20, 87% in treatment PS₂, a margin of profit of 7.63% was observed in PS₆ due to coarsely ground feed. It was concluded that increase in the feed particle size from 549 to 989 μ improved body weight gain as well as feed conversion ratio and resulted in to profitable broiler production.