Indoor birds? I don't use it myself, but I will also recommend the Kalmbach whole grain options, and echo the importance of serving as a wet mash or fermented feed, to ensure the fines (w/ the vitamin premix, some enzymes to improve digestibility/bioavailability, and other ingredients of nutritional benefit) are eaten with the grains.
There is no combination of common whole grains, which will meet a chicken's dietary needs - particularly certain amino acids making up the total crude protein - without either requiring that they eat far more feed than they typically would consume, grossly exceed their daily dietary energy needs, or both.
Something(s) need to be added to compensate for where grains are usually deficient. Adding seeds can help w/ some of the aminos, but while most seeds are higher protein than grains, they are still (typically) sub 16% crude protein as fed, while their contribution to dietary energy intake exceeds that of most grains. Non Phytate phosphorus (that is, phosphorus not in the form overwhelmingly found in plants) is needed to, as chickens almost can't use phytate phosphorus (unless you add an enzyme to make it more bioavailable).
The protein content of most grasses is typically well under that of a typical grain - which makes sense, as cereal grains are the seed of specialized grasses - and seeds are typically the most nutrient dense portion of a plant.
