New research released by sow breeding firm Topigs shows that 40,000 of its sows from 59 Dutch farms housed in groups produced piglets with a birth weight 61 grams higher than those housed individually. Results of the research, conducted in 2008-2009, were backed up by certain scientific papers, the company said.

Researchers cited a number of factors in reporting results: group housing allows sows to interact socially and perform beneficial behavioral patterns; group-housed sows exercise more; and group-housed sows lose less body energy through radiation in cold weather. European welfare regulations from 2013 onwards require sows to be housed in groups during gestation.