On the other hand, it has been reported that villus length, width and surface were reduced in birds fed barley-based diets (Moharrery and Mohammadpour, 2005). They also reported that villi length and surface gradually decreased from duodenum to ileum sections. Santin et al. (2001) reported that when birds were treated with 0.2% of yeast cell walls, villus height was increased and crypt depth was