The Codes of Recommendation for the Welfare of Livestock (pigs) recommends “Pigs should be kept in stable groups with as little mixing as possible”. In practice, mixing can not always be avoided, particularly towards the end of the finishing period. The present study investigated welfare aspects of mixing finishing pigs in two different types of accommodation.

A total of 240 finishing pigs (weight: 29.0 kg, SD=2.6 kg), housed in groups of ten, were subjected to a 2 x 4 factorial designed study. The factors were housing (two treatments) and mixing / moving (four treatments). The mixing treatments were applied at 55 and 75 kg average group weight, by either mixing half the group with half the pigs from another group in a pen unknown to both groups (MIX), or moving the pigs to a new pen (MOVE). The four mixing treatments therefore were: A (control). MOVE at 55 and 75 kg, B: MIX at 55 and MOVE at 75 kg, C: MOVE at 55 and MIX at 75 kg and D: MIX at 55 and 75 kg. The housing treatments were: scrape-through dunging area with strawed kennel (KEN) and strawed sloping floor without kennel (NO). Agonistic behaviour was recorded during the first two hours after MIX or MOVE, of four focal pigs in each group.