Enzyme supplementation and the inclusion of fibre in the barley-based diets have been some of the alternatives proposed to improve productivity in the absence of growth promoters. This study was performed to investigate the effect of adding sunflower hulls (SFH), a multi-enzyme carbohydrate, and feed forms (mash and pellet) on performance and some physiological parameters in broiler chickens fed barley containing diets. Treatments were two feed forms (mash vs. pelleted), and four diets consisted of a barley-based diet (control, CTL) or test diets which contained either SFH at 30 g/kg, enzyme (ENZ; 0.2 g/kg) or combination of SFH and enzyme (SFH + ENZ). The results showed that average daily feed intake and average daily gain were significantly increased in chickens that were fed ENZ (p < 0.05). The highest digestibility of ether extract (EE) was observed in the treatment containing SFH and SFH + ENZ (p < 0.05). The highest population of Lactobacillus spp. was observed in the treatment containing SFH (p < 0.05). The villus height and villus height to crypt depth ratios of duodenum and jejunum were significantly higher (p < 0.05) in broilers fed pellet diets compared to the mash. It can be concluded that pellet diets reduce digesta viscosity and harmful microorganisms (Escherichia coli), increase growth performance, and improve intestinal morphology in barley-based diets. Moreover, SFH and ENZ had favourable effects on EE digestibility and caecal microbial population of broilers fed with barley containing diets.