| Nosing | Nosing another part of the body of a penmate |
| Biting | Biting on substrates in pens |
| Mounting | Standing on hind legs while having front legs on another pig’s back (not the sows) |
| Tail biting | A pig chews, sucks or plays with another’s ears |
| Ear biting | A pig chews, sucks or plays with another’s tails |
| Aggression | Horizontal or vertical knocking with the head or forward thrusting with the snout toward a penmate; intense mutual/individual ramming or pushing a penmate; biting a penmate, except ear or tail |