Among the relative empty weight of digestive tracts, the gizzard weights of crumble-pellet fed birds were significantly (P < 0.05) lower than mash fed birds measured on day 41 ( Table 4). Further to that, the ileum weight decreased progressively with feed particle size, and the ileum length differed between birds fed crumble-pellet and mash diets. No feed particle size × feed form interaction for digestive tracts was observed.