Research Note: Is infrared thermography an appropriate method for early detection and objective quantification of plumage damage in white and brown feathered laying hens?

For the standardized assessment of plumage damage in laying hens, imaging techniques can be used in addition to visual plumage scoring (PS). In this study, the diagnostic accuracy of infrared thermography (IRT) was analyzed in white-feathered (WL) and brown-feathered laying hens (BL) with PS as a reference. In 28 flocks, a 3-level PS and IRT were performed 8 times for the dorsal neck, back, and belly plumage. A total of 3,600 records for WL and 7,600 records for BL were available for both PS and IRT in each of the 3 body regions. Receiver operating characteristic (ROC) analyses were used to investigate diagnostic accuracy. High-accuracy detection was found for severe plumage damage on the back (WL-sensitivity: 96.0%, specificity: 98.3%; BL-sensitivity: 96.1%, specificity: 98.9%) and belly plumage (WL-sensitivity: 96.3%, specificity: 95.7%; BL-sensitivity: 95.3%, specificity: 97.2%), but insufficient accuracy for distinguishing between intact plumage and moderate plumage damage in all 3 body regions (sensitivity: 31.7-71.5%; specificity: 70.4-98.1%). The area under the curve (AUC) of the ROC graphs differed significantly between BL and WL for the back and belly plumage (P ≤ 0.05). We concluded that IRT is a suitable tool to objectively detect severe plumage damage but not for early detection of incipient plumage loss.