4. Results
4.1. Association between sow pre-lying communication and piglet presence in the danger zone, sow area and piglet clustering
At least one piglet was present in the danger zone on Day 1 in 52.8% of standing-to-lying events (N = 66 out of 125 events) and on Day 3 in 13.3% (N = 18 out of 135 events) at the moment when the sow started to lie down. The proportion of piglets present in the danger zone increased significantly when the frequency of vocalization (P < 0.05) and sniffing (P < 0.05) increased. On Day 1, there was a higher proportion of piglets present in the danger zone than on Day 3 (P < 0.01, 15.5% piglets on Day 1 vs. 5.8% piglets on Day 3). All effects are shown in Table 2.