Table 2.

Ethogram.

Behavior	Description
Social behavior	Touching or sniffing any body part of a pen mate
Aggression	Uni- or bilateral fighting by chasing, head knocking (with or without biting), and/or pushing
Manipulate pig	Nibbling, sucking, or chewing on any body part of piglet or sow, or belly nosing
Manipulate pen	Nibbling, sucking, or chewing on pen components
Playing	Fast running around the pen (galloping), rolling, and shaking objects
Mounting	Standing on hind legs with front legs on pen mate