Journal of Veterinary Behavior: Clinical Applications and Research The influence of stocking density and enrichment on the occurrence of feather pecking and aggressive pecking behavior in laying hen chicks  Miriam Zepp, Helen Louton, Michael Erhard, Paul Schmidt, Franziska Helmer, Angela Schwarzer  Journal of Veterinary Behavior: Clinical Applications and Research  Volume 24, Pages 9-18 (March 2018) DOI: 10.1016/j.jveb.2017.12.005 Copyright © 2018 Elsevier Inc. Terms and Conditions

Figure 1 Overview of the functional areas and the placement of the video cameras in 2 sections of the aviary. Schematic illustration from above (not true to scale) of the functional areas on the second floor of the aviary system and in the litter area on the ground and the placement of the video cameras. Journal of Veterinary Behavior: Clinical Applications and Research 2018 24, 9-18DOI: (10.1016/j.jveb.2017.12.005) Copyright © 2018 Elsevier Inc. Terms and Conditions

Figure 2 Estimated effect of functional areas on the occurrence of pecking. Diagram showing the estimated effect and the 95% confidence interval (CI) of observed functional areas on the occurrence of enrichment pecking (A), gentle feather pecking (B), severe feather pecking (C), and aggressive pecking (D). Results were considered significant when the CI did not include zero. Estimated effects above 0 indicate an increase in the chance of observing a behavioral parameter, whereas estimated effects below 0 indicate a decrease. Journal of Veterinary Behavior: Clinical Applications and Research 2018 24, 9-18DOI: (10.1016/j.jveb.2017.12.005) Copyright © 2018 Elsevier Inc. Terms and Conditions

Figure 3 Estimated effect of the day of life on the occurrence of pecking. Diagram showing the estimated effect and the 95% confidence interval (CI) of the evaluated days of life on the occurrence of enrichment pecking (A), gentle feather pecking (B), severe feather pecking (C), and aggressive pecking (D). Results were considered significant when the CI did not include 0. Estimated effects above 0 indicate an increase in the chance of observing a behavioral parameter, whereas estimated effects below 0 indicate a decrease. Journal of Veterinary Behavior: Clinical Applications and Research 2018 24, 9-18DOI: (10.1016/j.jveb.2017.12.005) Copyright © 2018 Elsevier Inc. Terms and Conditions

Figure 4 Estimated effect of experimental groups on the occurrence of pecking. Diagram showing the estimated effect and the 95% confidence interval (CI) of experimental groups on the occurrence of enrichment pecking (A), gentle feather pecking (B), severe feather pecking (C), and aggressive pecking (D). Results were considered significant when the CI did not include 0. Estimated effects above 0 indicate an increase in the chance of observing a behavioral parameter, whereas estimated effects below 0 indicate a decrease. Estimated effect of enrichment pecking was observed only between groups 3 and 2, because enrichment was not provided in group 1. Journal of Veterinary Behavior: Clinical Applications and Research 2018 24, 9-18DOI: (10.1016/j.jveb.2017.12.005) Copyright © 2018 Elsevier Inc. Terms and Conditions