A preference-testing apparatus was designed to provide sows with continuous access to three farrowing crates of different widths. The crates radiated from a central hub area sufficiently large for sows to enter or leave any crate freely. In exp. 1, nine sows were offered crates of 450-, 600- and 750-mm width at standing height. In exp. 2, 12 sows were offered widths of 450, 750 and 1200 mm, the largest being of sufficient width for the sow to turn around. Video recording was used to determine sow position from 3 d before to 6 d after farrowing. In exp. 1, sows showed a preference for the widest crate of 750 mm during and after farrowing (P < 0.05) but not before. ln exp. 2, the 1200-mm width was preferred before, during and after farrowing (P < 0.005) over the widths that were too narrow to permit turning. Sufficient space for turning appears to be preferred by sows around the time of farrowing.
Phillips, P. A., Fraser, D., & Thompson, B. K. (1992). Sow preference for farrowing-crate width. Canadian Journal of Animal Science, 72(4), 745-750.