Effect of feed particle size on the performance of broiler chickens

The present study was undertaken to investigate the effect of particle size on the performance of broiler chicken and economics of grinding. Three hundred, day old broilers chicks were procured and were offered the starter ration from 0–4 weeks of age and finisher rations from 4–6 weeks of age. The ingredients composition of all the five treatments was similar only with the difference of particle size. The different feed particle sizes were achieved by using different hammer mill screen sizes i.e. T₁ (2mm), T₂ (3mm), T₃ (4mm), T₄ (5mm) and T₅ (6mm). Screen hole size significantly effected the particle size, modulus of fineness, electricity consumption, time consumption in grinding and performance of birds. The weight gain was significantly (P<0.05) higher for the birds of treatment T₂ and T₅ as compared to other treatments. The feed conversion ratio was better in treatment T₄ as compared to all other treatments. The FCR improved with the increase in particle size up to 868 microns (5mm screen size). The FCR was further increased when 6mm screen size feed particle size was offered. The difference in the weight of gizzard, heart, intestine and dressing (as percent of body wt.) was non-significant (P<0.05) among the treatments. However, the wt. of liver as percent of total live wt. was significantly (P<0.05) higher in T₁ and T₅ as compared to T₂, T₃ and T₄. It was inferred that the feed particle size resulted by using 5mm opening screen size mill was most efficiently utilized by the birds, as it resulted in improved FCR, reduced electricity consumption for grinding and better body weight gains in birds.