O'Connor, E. A., Saunders, J. E., Grist, H., McLeman, M. A., Wathes, C. M., & Abeyesinghe, S. M. The relationship between the comb and social behaviour in laying hens. Applied Animal Behaviour Science, 135(4), 293-299. https://doi.org/10.1016/j.applanim.2011.09.011