Gestating sows are housed in a series of gestation stalls arranged in a row and backing onto an open alley along a rear of the row of stalls into which the sow can enter by backing out of the stall. A common trough extends along the front of the stalls and is fastened to the floor by fasteners which connect trough sections end to end. The common trough provides a support for the front end of the side walls defining the stalls. A rear gate closes the rear of each stall and connects to a front gate of the stall operable to close the rear gate by the sow as it moves in the stall toward the front. The rear gate latches closed to prevent entry of another sow but is releasable by rear pressure on the rear gate from the sow backing out.