Automatic Assessment of Keel Bone Damage in Laying Hens at the Slaughter Line

Abstract

Keel bone damage (KBD) can be found in all commercial laying hen flocks with a wide range of 23% to 69% of hens/flock found to be affected in this study. As KBD may be linked with chronic pain and a decrease in mobility, it is a serious welfare problem. An automatic assessment system at the slaughter line could support the detection of KBD and would have the advantage of being standardized and fast scoring including high sample sizes. A 2MP stereo camera combined with an IDS imaging color camera was used for the automatic assessment. A trained human assessor visually scored KBD in defeathered hens during the slaughter process and compared results with further human assessors and automatic recording. In a first step, an algorithm was developed on the basis of assessments of keel status of 2287 hens of different genetics with varying degrees of KBD. In two optimization steps, performance data were calculated, and flock prevalences were determined, which were compared between the assessor and the automatic system. The proposed technique finally reached a sensitivity of 0.95, specificity of 0.77, accuracy of 0.86 and precision of 0.81. In the last optimization step, the automatic system scored on average about 10.5% points lower KBD prevalences than the human assessor. However, a proposed change of scoring system (setting the limit for KBD at 0.5 cm deviation from the straight line) would lower this deviation. We conclude that the developed automatic scoring technique is a reliable and potentially valuable tool for the assessment of KBD.

Automatic Scoring System for Monitoring Foot Pad Dermatitis in Broilers

“…The differences were only marginal, and the accurate estimation was probably caused by the large sample size. The results are in line with a study by Jung et al [34], who found that optimizations of algorithms led to an improvement in the detection of keel bone damage in automatic assessments. The authors observed that the camera system generally underestimated the presence of keel bone damage.…”

“…Macro Score 4 was allocated to Macro Score 3, and with the threshold values of 12.66 (original camera score) and 16.68 (updated camera score), these scores were well diagnosable with a sensitivity of 0.82 (original camera score) and 0.81 (updated camera score) and a specificity of 0.80 (original camera score) and 0.87 (updated camera score). Jung et al [34] examined the automatic assessment of keel bone damage using a similar camera system as described in our study. After optimizations of the system, the authors reached a sensitivity of 95% and a specificity of 80% from the previously determined sensitivity of 28% and specificity of 66%.…”

A comparison of online and live training of livestock farmers for an on-farm self-assessment of animal welfare

“…On the individual test level, the farmers reached mean PABAK values representing substantial to almost perfect agreement. The PABAK means did not differ substantially compared to those reported from reliability tests performed by scientists (using PABAK), for example for keel bone damage in laying hens (Jung et al, 2021); manure on the body of pigs (Wimmler et al, 2021); body condition, lameness, and cleanliness in dairy cows (Wagner et al, 2021); footpad dermatitis in turkeys (Stracke et al, 2020) or broilers (Piller et al, 2020;slightly higher in Louton et al, 2019); and stereotypies, skin lesions, underconditioning, and lameness in sows (Friedrich, 2018). For some of the indicators in our study, the reliability was relatively low and showed potential for improvement by using fewer score levels or modified definitions.…”

“…Additionally, adverse environmental conditions such as poor light and moving animals can impair the recognition of certain findings or distract the assessor on-farm. Some indicators, such as keel bone damage in laying hens (Jung et al, 2021) or underconditioning in sows (Welfare Quality ® Consortium, 2009b) are commonly assessed by palpation, and some findings might appear differently from the threedimensional view in the two-dimensional pictures. Therefore, a final evaluation of the two methods should additionally take into account an on-farm inter-rater reliability assessment.…”

“…The outcomes of the on-farm self-assessments by the farmers need to be sufficiently reliable to allow valid evaluations using reference values or comparisons with previous recordings and the results of other farms (benchmarking). For scientific investigations, it is well documented that adequate inter-rater reliability is supported by training (Brenninkmeyer et al, 2007;March et al, 2007;Gibbons et al, 2012;Vasseur et al, 2013;Vieira et al, 2015;Croyle et al, 2018;Jung et al, 2021). Furthermore, inter-rater reliability should be tested and should reach certain minimum values (Knierim and Winckler, 2009).…”