Fig. 3From: Application of the voluntary human approach test on commercial pig fattening farms: a meaningful tool?Percentage of pigs relative to group size [%] surrounding the observer after one minute (PPSO) according to group size (1 = 1–12, 2 = 13–20, 3 = 21–35, 4 = 36–50, 5 = 51–100, 6 > 100 pigs per pen)Back to article page