Group composition for fattening entire male pigs under enriched housing conditions—Influences on behaviour, injuries and boar taint compounds

•Single-sex and mixed-sex groups with entire and castrated males were compared under enriched housing conditions.•Groups with entire males did not differ in terms of behaviour.•Welfare of female pigs was not impaired when penned together with entire males.•More skin lesions were detected in single-sex compared to mixed-sex groups. In organic farming, the production of pork from entire male pigs seems to be the most promising alternative to castration, as organic animal husbandry aims at high standards of animal welfare and elimination of mutilations. However, previous research on behaviour of entire male pigs was mostly carried out under barren housing conditions and is thus not entirely transferrable to enriched housing conditions. In the present study, we investigated single-sex and mixed-sex groups of entire male pigs and compared them with mixed-sex groups of castrated male pigs under organic housing conditions. On a commercial farm, 362 pigs (average weight 22.7kg, average age 80 days) were assigned to pens with groups of 20 (+1) pigs according to three treatments: single-sex groups with entire males (EE), mixed-sex groups with entire males and females (EF) and mixed-sex groups with castrated males and females (CF). Skin and tail lesions, lameness and the behaviours ‘head knocking/biting’, ‘fighting’ and ‘mounting’ were assessed on five days during the fattening period. Average carcass weight for all sexes was 92kg. After slaughter, female reproductive organs were inspected for signs of pregnancy. Fat samples of entire male pigs were analysed for concentrations of androstenone and skatole. Entire males showed more aggressive and mounting behaviours than castrated males (p