The time to change from a standing to a lying posture is negatively correlated with stall length relative to female length (Anil et al., 2002). Although we did not measure the intervals from one posture to another posture, females in late gestation and old-parity sows may be more reluctant to move than females in early gestation and young gilts because of their body size. The physical space requirement of the females may also have to be reconsidered (Curtis et al., 1989).