A number of studies have been carried out on open pen farrowing systems and where these systems have appeared to function well, the minimum pen dimension has been 2.2m. The original pen system at ADAS Terrington had a maximum width of about 1.5m - the space occupied by a pen with a farrowing crate. The aim of this experiment was to determine whether increasing the pen width affected sow behaviour and production in a three-sow group farrowing system.

A total of 36 LW x Landrace sows of similar genetic stock (PIC, Abingdon, UK) and ranging from 1st to 7th parity were studied from 7 days before farrowing until 7 days after farrowing. The farrowing systems comprised three individual strawed pens, a communal passageway and an outdoor dunging area. Each pen had a heated creep at the rear and sloping walls along the sides of the pen with a piglet escape area at the bottom. Four replicates of 3 sows were studied in the Narrow Pen (width = 1.6m) treatment and eight replicates of 3 sows were studied in the Wide Pen (width = 2.4m) treatment.