Effects of food and time of day on aggression when grouping unfamiliar adult pigs (1994)

Barnett, J. L., Cronin, G. M., McCallum, T. H. et al.

Abstract

The lower incidence of aggressive interactions during the initial period of grouping in the dark treatment may have been due to the pigs usually having 'settled' for the night by this time. ... There may be potential welfare advantages in reducing aggression by grouping unfamiliar adult pigs after dark and subsequently providing ad libitum food to reduce aggression at feeding.