A preference testing apparatus was designed to give sows continuous access to three farrowing crates with different degrees of visual enclosure. A ‘fully enclosed' crate had solid black panels on the sides and top of the crate, a ‘solid-sided’ crate had the side panels only and an ‘open crate’ had no solid panels over the crate's tubular framework. The crates radiated from a central area sufficient for sows to enter or leave any crate freely. Video recording was used to determine sow position from 3 days before to 6 days after farrowing. The results indicated that younger sows (second or third panty) preferred the enclosure offered by the solid side panels during and for several days after farrowing (P < 0.05). Older sows, which had previously farrowed a number of times in an open crate, had no clear preference. A solid panel overhead did not improve, and may have reduced, the acceptance of a crate with solid sides. It is concluded that less experienced sows prefer a degree of enclosure on the sides of the farrowing crate, but that this preference largely disappears with repeated experience of open crates.
Phillips, P. A., Fraser, D., & Thompson, B. K. (1991). Preference by sows for a partially enclosed farrowing crate. Applied Animal Behaviour Science, 32(1), 35-43.