Table 1. Ethogram used to record sow behaviors during the experiment

Category Behavior Description
Basic behaviors Standing The body weight was supported by the 4 legs. Included standing and walking
Lying The sow maintaining a recumbent position
Lying to flattening The sow lies on the flattening floor while the head is resting on the ground or is erected
Unusual behaviors Fighting Forceful pushing on other sows
Chewing Chewing actions were performed without the presence of food in the oral cavity.If performed excessively, sham chewing may be accompanied by hyper-salivation. Sham chewing occurs most frequently in confined sows fed a highly concentrated diet and is considered to be a vacuum activity
Scratching Any repeated or rhythmical rubbing action against objects in the surroundings (e.g., wall, ground surface, etc.) or rubbing action between two parts of a sow’s own body.
Grouping The formation of a group of sows by natural means (e.g., herd formation as a result of social attraction) or by human action