Barley, oats, and wheat were stored anaerobically for three months after adjusting the dry matter content to 60%. The content of true protein was reduced when grains were high‐moisture stored, but the amino acid content was not affected to the same extent. High‐moisture storage decreased the soluble dietary fibre and solubleβ‐glucan content in barley and oats, and simultaneously the extract viscosity of the grain was reduced to the same level as for wheat. In two experiments with two to five week old broiler chickens given diets with 70% dried or high‐moisture stored grain, feed:gain ratio was reduced (P <0.05) to the same level as for the wheat diets when high‐moisture stored barley instead of dried barley was fed, and digestibility of dry matter, organic matter, fat, and minerals increased (P <0.05). Weight gain and cleanness of cages also increased (P <0.05), and the relative size of the digestive tract was reduced (P <0.05). Digestibility of dry matter, organic matter, and minerals increased (P <0.05) when highmoisture stored oats compared to dried oats were fed, and highmoisture storage of wheat increased (P <0.05) P and Ca digestibility.