In an experiment carried out on 384 broiler chickens, the following parameters were compared: weight of the gizzard, pH of the digesta in the gizzard and in the small intestine, as well as the extent of digesta disintegration in this part of the digestive tract. The birds were fed diets containing either whole or ground wheat grain. In addition, the effect of an enzymatic preparation containing xylanase on the examined parameters was determined. It was found that whole grain fed to broiler chickens increased the weight of the gizzard, decreased the pH of the digesta in the gizzard and increased the pH in the small intestine. The physical form of the wheat grain was not found to influence the degree of digesta disintegration in the small intestine.