Fig 1.
Positioning of the animal on the X-ray detector.
The red lighted area indicates the radiation field center.
Fig 2.
The keel bone surface area is circumscribed with blue color; the area of deviation is circumscribed with red color. The blue-red line marks the straight line between the start and end point of thedeviated outline.
Fig 3.
A fractured keel bone with callus formation.
The arrow shows the fracture callus.
Fig 4.
A fractured keel bone without callus formation.
The arrow shows the fracture, a thin, black line.
Fig 5.
Each bar represents the total amount of radiographed and evaluated hens of one layer line within one housing system. The grey part of a bar shows the part of hens with a deviated keel bone, the white part those without any deviation. The numbers written in the bars show the total numbers of affected or non-affected hens, respectively. Prevalence of deviations was affected by layer line (p<0.05). There was no significant influence of housing system (p>0.05) or age (p>0.05) on prevalence of deviations.
Fig 6.
Proportion of deviated keel bone area (POD) (back-transformed LSM and upper and lower bounds of the 95% confidence interval) in %.
POD was affected by the three-way interaction between housing system, layer line and age (p<0.01).
Fig 7.
Each bar represents the total amount of radiographed and evaluated hens of one layer line within one housing system. The grey part of a bar shows the part of hens with a fractured keel bone, the white part those without any fracture. The numbers written in the bars show the total numbers of affected or non-affected hens, respectively. Fracture prevalence was affected by layer line (p<0.05 at all three ages) and age (p<0.001). Housing system significantly influenced fracture prevalence in the 72nd week of age (p<0.05).