Fig. 4
From: Differences in hindlimb morphology of ducks and chickens: effects of domestication and selection
Rotation of the distal part of the femur and tibiotarsus in relation to the proximal part of the femur and tibiotarsus, respectively. Angles at the starting point at 3 weeks of age are based on the relative position of bone landmarks and are not a measure of initial rotation. A decrease in angle after 3 weeks represents external femoral rotation and internal tibiotarsal rotation