The objective of this research was to explore different environmental factors that may be associated with the development and performance of oral-nasal behaviour problems, particularly belly nosing, common to newly-weaned piglets. In two experiments, the relationship between cold draft and belly nosing, and the relationship between hunger and belly nosing, were investigated. The presence of cold draft stimulated nosing and chewing the ears and tails of pen-mates and reduced the performance of belly nosing behaviour. Reduction in time spent belly nosing may have been a result of increased activity and time spent at the feeder, suggesting that cold draft may indirectly affect the performance of this behaviour. Hunger, through feed restriction (65% of ' ad libitum' intake), increased time spent nosing and chewing the pen, which was most likely related to foraging behaviour. Hunger also appeared to stimulate the performance of belly nosing behaviour on an individual basis, but not on a group basis. This suggests that belly nosing is associated with hunger motivation. While it elicits belly nosing in those piglets that already have a tendency to engage in the behaviour, it does not cause the development of this behaviour in others.