Group housing for pregnant sows is increasingly adopted as a welfare improvement, but implementation quality varies enormously.
Group housing sows in poorly managed systems can experience worse welfare than crate-housed sows due to fighting and bullying. When sows are mixed without careful management, injuries from aggression are common. Space allocation below minimum requirements causes chronic stress. Feed competition in inadequate systems leaves subordinate sows undernourished. Well-implemented group housing provides substantially better welfare, but poor implementation can cause significant harm. Management quality matters more than housing type alone.