A chain tensioning apparatus for tensioning a chain of an agricultural barn cleaner. The barn cleaner chain is moved by a motor-driven drive sprocket mounted in a drive tower after contacting a first idler rotatably mounted to the drive tower. A second idler is mounted to the frame and positioned further away from the drive tower than the first idler such that, as the chain moves toward the drive tower, the chain contacts the second idler before contacting the first idler. A chain tensioning idler contacts the chain between the first idler and the second idler and is capable of movement in a direction transverse to the movement of the chain. A biasing member biases the chain tensioning idler toward a take-up position and away from a chain-taut position.
