Four growth experiments were conducted on 304 one-week old broiler cockerels to determine the response of chickens to the increasing levels of rye and its soluble arabinoxylans (SAX) in the diet. Substituting more than 10% of maize with rye depressed body weight gain and substituting more than 20% decreased the feed conversion ratio in chickens. However, i f the lower AME value of rye was compensated for by sunflower oil supplementation the tolerated level of rye in a maize diet increased about threefold, corresponding to about 0.9% of dietary rye SAX. Similar results were obtained when rye SAX preparation was added to a wheat diet. Reducing the dietary SAX content to about 1.4% in the diets with rye hybrids, which were selected for better feeding quality, resulted in a noticeable improvement of chick performance. The nutrition parameters obtained in chickens fed the diets based on these hybrids were not significantly different as compared with wheat diet and significantly better as compared with population rye diet containing about 2.07% dietary SAX.