Table 1.

A simplified summary of previous research reporting main findings of welfare indicators of keel bone damage reviewed in this article.

	Indicator
Reference	Behavioral	Physiological	Clinical	Affective state	Production
(14)	↑ Sleep on floor ↓ Use of perches ↑ Latency fly off perches ↑ Duration walkway test	↓ Temperature around keel ↓ Keel bone strength	No difference BW	N/A	↓ Eggs laid ↓ Eggshell weight ↑ Lighter egg weight ↓ Egg surface area
(71)	N/A	N/A	N/A	↓ Latency fly off perch after analgesics	N/A
(70)	↓ Use of pop-holes	N/A	N/A	N/A	N/A
(82)	N/A	↓ Tibia ash content ↓ Tibia breaking strength	No difference BW No difference girth or wing:girth ratio ↓ Feather coverage	N/A	N/A
(77)	N/A	N/A	N/A	CPP formed with analgesics	N/A
(83)	N/A	↓ Keel bone strength	No difference BW No difference in egg deformation, blood spots or calcification	N/A	↑ Feed intake ↑ Water intake ↓ Eggs laid ↓ Egg weight
(13)	N/A	↓ BMD keel surface ↓ peak load failure tibia	N/A	N/A	N/A
(19)	↑ Time in nest boxes after keel fracture No difference night perch use	N/A	↑ Incidence of bumble foot	N/A	Earlier first egg appearance No difference total egg number
(86)	N/A	N/A	N/A	N/A	↑ Bone splinters in breast muscle
(69)	↓ Time standing ↓ Standing bouts ↑ Time perching ↑ Rest on perches	N/A	N/A	N/A	N/A
(85)	N/A	N/A	N/A	N/A	↓ Laying performance ↑ Egg weight
(24)	N/A	N/A	N/A	N/A	↓ Egg production ↓ 2nd quality eggs
(98)	No difference in balance measures while perching No difference latency to fly off perch	N/A	N/A	N/A	N/A
(99)	N/A	↓ Keel calcium content ↓ Tibia shear strength	↑ Body mass	N/A	N/A
(84)	N/A	N/A	N/A	N/A	↓ Eggshell strength
(100)	N/A	N/A	↓ Poor plumage condition	N/A	N/A

The text lists measures where birds with keel bone fractures differed significantly from the non-fractured birds as well as measures where no differences were found.

N/A, not available; BW, body weight; CPP, conditioned place preference; BMD, bone mass density.