Ingredient particle size and feed texture: effects on the performance of broiler chickens

In two experiments female and male broiler chickens were given starter (1–21 days) and grower (22–42 days) diets that were fine mash (FM), fine mash pelleted (FMP), coarse mash (CM), coarse mash pelleted (CMP) or very coarse mash (VCM). The FM was produced by grinding the dietary corn and wheat with hammer mills containing 3.2 mm and 4.0 mm screens, respectively, and the CM by grinding the corn in a hammer mill (5.6 mm) and passing the wheat through a roller mill (1.6 mm spacing between the rollers). A roller mill was used to produce the VCM, with spacing of 3.2 mm and 2.4 mm for the corn and wheat, respectively. All birds received four cycles per 24 h of 4 h light and 2 h dark. Pelleting of either the FM or CM diets improved (P < 0.001) 21 day (9.6% and 5.6%, respectively) and 42 day (9.8% and 6.5%, respectively) body weights, feed conversions (respectively 2.1% and 5.6% for 1–21 days, and 4.1% and 5.0% for 1–42 days) and monetary returns (14.0% and 10.2%, respectively) over feed and chick costs. Also, 42 day body weights were different (P < 0.01) among the mash diets (1942 g FM, 1982 g CM and 2004 g VCM). Ingredient particle size and feed texture had little effect (P > 0.05) on mortality from sudden death syndrome (SDS). As expected, mortality, including that from SDS, body weights and monetary returns were lower (P < 0.01) and feed conversions poorer (P < 0.05) for the female than male chickens. Improved productive performance can be expected when broiler chickens are given pelleted diets, probably as a result of increases in daily nutrient intakes and digestibility of dietary carbohydrates associated with pelleting.