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Lay Jr., D.C., Fulton, R.M., Hester, P.Y., Karcher, D.M., Kjaer, J.B., Mench, J.A., Mullens, B.A., Newberry, R.C., C.J., O'Sullivan, N.P. and Porter, R.E., (2011). Hen welfare in different housing systems. Poultry Science, 90: 278-294 doi10.3382/ps.2010-00962
Bennewitz, J.; Bögelein, S.; Stratz, P.; Rodehutscord, M.; Piepho, H. P.; Kjaer, J. B.; Bessei, W. (1 de abril de 2014). «Genetic parameters for feather pecking and aggressive behavior in a large F2-cross of laying hens using generalized linear mixed models». Poultry Science(en inglés)93 (4): 810-817. ISSN0032-5791. PMID24706957. doi:10.3382/ps.2013-03638.
Bennewitz, J.; Bögelein, S.; Stratz, P.; Rodehutscord, M.; Piepho, H. P.; Kjaer, J. B.; Bessei, W. (1 de abril de 2014). «Genetic parameters for feather pecking and aggressive behavior in a large F2-cross of laying hens using generalized linear mixed models». Poultry Science(en inglés)93 (4): 810-817. ISSN0032-5791. PMID24706957. doi:10.3382/ps.2013-03638.