Effect of wheat coarseness and pellet quality on performance and particle size preference of broiler chickens fed diets based on wheat and maize

Recent broiler experiments have demonstrated that the macrostructure defined as the diameter and length of pellets can be larger, and that the tolerance for fines in the diet is higher than currently assumed. In a first experiment, broiler performance till 10 d of age was not affected when a 3 mm pelleted diet was replaced with a 5 mm pelleted and crumbled diet (35% particles > 3.6 mm). Preference tests indicated either no particle size preference, or a preference for particles > 2.8 mm. In a second experiment, reducing pellet quality of 5 mm pellets to increase the amount of fines had no effect on weight gain and FCR from 10 to 34 d of age, but when diets consisted of finely ground wheat as compared to coarsely ground wheat, the feed intake was higher and FCR was poorer. When offered feed with particles > 4.0 mm, 2.8 to 4.0 mm, 1.6 to 2.8 mm and < 1.6 mm, broilers ate more particles 1.6 to 2.8 mm than > 4.0 mm at 12 d of age, while no clear particle size preferences were observed at older ages. These data confirm that diets pelleted through a 5 mm die can be used even from day-old, and that broilers can handle a moderate reduction in pellet quality of 5 mm pellets without compromising performance. A high versatility of broiler chickens to particle size variations, and a preference for larger particles than currently assumed even at a very young age, may explain these results.