The effect of feed particle size, milling method, and thermal treatment, on interior and exterior egg quality in laying hens

Quality egg production is the ultimate goal of layer farming. The grinding of grains to a more uniform particle size may improve the performance of mature birds (Amerah et al., 2007). Two methods, including hammer mill and roller mill, are commonly used to reduce particle size of grains (Amerah et al., 2007). Thermal treatment of feed is commonly used for feed sanitation, which may improve bird's performance (Kilburn and Edwards, 2001). The effect of the mentioned treatments on performance of poultry has widely been studied, however the knowledge regarding their impact on egg quality is limited. Therefore, the present study was designed to investigate the effects of feed grinding technique (roller (R) vs. hammer mill (H)), form of compaction (mash (M) or expandate (E)), and grinding intensity (coarse (C) vs. fine (F) particle size) on interior and exterior egg quality in layers.