Table 1.

Ethogram used for behavior observations.

Behavior	Description
General activity
Forage	Pecking or scratching at the floor of the cage with head below rump [adapted from Klein et al. (25)]. Can include scratching motion with legs but does not include feather pulling/pecking on other birds
Eat	Head in the feed trough or completely through the cage over the feeder. Can include standing breaks of ≤5 s followed by resumption of behavior
Drink	Repeated pecks at nipple drinker followed by swallowing. Can include standing breaks of ≤5 s, with beak still within the plane of the drinker, followed by resumption of drinking behavior
Preen	A hen uses her beak to clean wing and body feathers. Related behaviors include head scratching, wing stretching, feather ruffling, and/or feather erection
Walk	Moving more than three paces in one direction, head erect
Stand	Hen standing on feet, legs extended, no movement of the body but with eyes open [adapted from Webster and Hurnik (26)]. Head in either erect or relaxed posture
Sit	Hen’s body is flush with the bottom of the cage, wings tucked, and head either erect or in relaxed posture. Eyes are open
Sleep	Hen in a relaxed posture, either sitting or standing, with eyes closed. Head may be tucked [adapted from Blokhuis (27)]
Dust bathe	A hen performs vertical wing shakes on the wire, bill raking, circular foot motions. Includes sham dustbathing. Hen may pull feed from feeder to use as substrate. Can be social or individual [adapted from Scholz et al. (28)]
Perch	A hen has two feet on a perch (or feed auger) for more than 3 s (i.e., not stepping over the perch)