Effect of Corn Grinding Methods and Particle Size on the Nutrient Digestibility of Chahua Chickens

This study investigates the effect of grinding methods, including roller mill, hammer mill, and two-stage grinding, on the particle size distribution of corn and the effect of corn particle size on the nutrient digestibility of native chickens in Southwest China. The roller mill, hammer mill, and a combination of the hammer mill and roller mill were used to obtain corn with various coarseness. Corn with different coarseness obtained using a combination of the hammer mill and roller mill was fed to Chahua chicken No. 2-type chickens (CHC2s). A total of 192 CHC2s in weeks 12 and 19 were randomly allocated to eight groups in triplicate. The results show that the geometric mean diameter (d ) and the geometric standard deviation (S ) were significantly ( < 0.05) affected by the grinding methods. The S obtained when using a sieve of 2.0 mm in a hammer mill was lower ( < 0.05) than that obtained using a 4.5 mm sieve. Combining the roller mill and hammer mill increased the uniformity of the particle size when grinding coarse particles. For fine particles, the d and S obtained when using the hammer mill were significantly lower ( < 0.05) than those obtained when using the roller mill and two-stage grinding method. Reducing the particle size of the corn (