Practical test: Strautmann Verti-Mix 1300 Double K feeder Build height has long been a criticism of vertical-auger feeders when mounted over conventional running gear. Strautmann’s solution? To develop the Verti-Mix Double K, a machine that combines compactness of construction while still retaining a decent 13m³ capacity and substantial footwear beneath. Here profi’s test team picks out the pros and cons of the design