| Oral manipulation of group mates |
|
| Tail biting |
Nibbling, sucking or chewing the tail of a pen mate |
| Ear biting |
Nibbling, sucking or chewing the ear of a pen mate |
| Manipulating other |
Nibbling, sucking or chewing of another part of the body of a pen mate |
| Aggression |
|
| Fighting |
Ramming or pushing a pen mate with or without biting the other pen mate. Can be either mutual or unilateral |
| Fighting at feeder |
Pushing, head knocking or biting a pen mate at the feeder |
| Belly nosing |
Rubbing the belly of a pen mate with up and down snout movements |
| Mounting |
Standing on hind legs while having front legs on other pig's body |
| Enrichment object biting |
Chewing on an enrichment object provided in the pen. The enrichment object was a chain with a hard plastic pipe fixed at the top of the pen wall. |
