The addition of flax and hemp seed or their combination in the mixed feed seems to have a very favorable effect on increasing the activity of enzymes and digestibility of nutrients, supplementing substances beneficial for the organism, increasing growth parameters of chickens and reducing feed conversion. The main enzymatic transformation occurred in the ileum, where the addition of hemp and flaxseed to the feed increased enzyme activity the most. The highest level of enzyme activity was recorded in the feed with a combination of flaxseed and hemp seed at the level of 80 and 50 g/kg. The main increase in the activity of enzymes (amylase, cellulase, pectinase, xylanase, maltase, invertase, proteinase and lipase) at the level of the ileum was shown by all groups with the addition of hemp seed. These results showed the benefits of using diets containing flaxseed and hempseed, and especially a combination of both.