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Keel bone injury in laying hens: the prevalence of injuries in relation to different housing systems, implications, and potential solutions

  • E. HARDIN (a1), F.L.S. CASTRO (a1) and W.K. KIM (a1)


Increased pressure on the poultry industry by animal-rights organisations and environmentally-conscious consumers has led to the rising popularity of cage-free housing system for hens. One of the main dangers of cage-free housing systems is the possibility for laying hens to damage their keels. Keel bone fracture incidence rate ranges up to 85%, and can lead to extensive pain in any bird, and potentially be the cause of the death for a hen in a cage-free environment. It was reported that kneel bone damage observed in flocks housed in non-cage systems was 30 to 95% while in furnished cages it was 15 to 55%. The purpose of this review is to compare the prevalence of the problem found in the three main housing systems (conventional, enriched cage, and cage-free), discuss if such damage could affect the behaviour and production of laying hens, and provide potential solutions for reducing the prevalence of keel bone damage. Keel fractures can negatively affect a hen in its day-to-day life by causing pain and restricting its movements. The prevalence of keel bone damage varies considerably among the studies due to differences in the system design, genetic line, age and method for determining the keel damage, which makes difficult to compare the systems. The genetic selection, adequate nutrition and modifications in the house design have shown to be useful tools in reducing keel bone damage in laying hens.


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APPLEBY, M.C. (2003) The European Union Ban on Conventional Cages for Laying Hens: History and Prospects. Journal of Applied Animal Welfare Science 6: 103-121.
BUCKNER, G.D., INSKO, W.M., HENRY, A.H., WACHS, E.F. and MACLAURY, D.W. (1947) Rates of growth and calcification of the sternum of male and female new-Hampshire chickens. Poultry Science 26: 533-534.
CANDELOTTO, L., STRATMANN, A., GEBHARDT-HENRICH, S.G., RUFENER, C., VAN DE BRAAK, T. and TOSCANO, M.J. (2017) Susceptibility to keel bone fractures in laying hens and the role of genetic variation. Poultry Science 96: 3517-3528.
CASEY-TROTT, T.M., HEERKENS, J.L., PETRIK, M., REGMI, P., SCHRADER, L., TOSCANO, M.J. and WIDOWSKI, T.M. (2015) Methods for assessment of keel bone damage in poultry. Poultry Science 94: 2339-2350.
CASEY-TROTT, T.M. and WIDOWSKI, T.M. (2016) Behavioral Differences of Laying Hens with Fractured Keel Bones within Furnished Cages. Frontiers in Veterinary Science 3 (42): 1-8.
CASEY-TROTT, T.M., GUERRIN, M.T., SANDILANDS, V., TORREY, S. and WIDOWSKI, T.M. (2017) Rearing system affects prevalence of keel bone damage in laying hens: a longitudinal study of four consecutive flocks. Poultry Science 96 (7): 2029-2039.
CLAESSENS, L.P. (2009) The skeletal kinematics of lung ventilation in three basal bird taxa (emu, tinamou, and guinea fowl). Journal of Experimental Zoology Part A: Ecological Genetics and Physiology 311A: 586-599.
DOYON, M., BERGERON, S., CRANFIELD, J., TAMINI, L. and CRINER, G. (2016) Consumer Preferences for Improved Hen Housing: Is a Cage a Cage? Canadian Journal of Agricultural Economics/Revue Canadienne Dagroeconomie 64: 739-751.
DUNCKER, H.R. (2000) The respiratory apparatus of birds and their locomotory and metabolic efficiency. Journal of Ornithology 141: 1-67.
FLEMING, R.H., MCCORMACK, H.A., MCCTEIR, L. and WHITEHEAD, C.C. (2004) Incidence, pathology and prevention of keel bone deformities in the laying hen. British Poultry Science 45: 320-330.
GREGORY, N.G. and WILKINS, L.J. (1989) Broken bones in domestic fowl: handling and processing damage in end-of-lay battery hens. British Poultry Science 30: 555-562.
GUIONETTE, F., GAUTRON, J., NYS, Y. and SOURMARMON, A. (1995) Calcium solubilisation and retention in the gastrointestinal tract in chicks (Gallus domesticus) as a function of gastric acid secretion inhibition and of calcium carbonate particle size. British Journal of Nutrition 73: 125-139.
HEERKENS, J.L., DELEZIE, E., AMPE, B., RODENBURG, T.B. and TUYTTENS, F.A. (2016) Ramps and hybrid effects on keel bone and foot pad disorders in modified aviaries for laying hens. Poultry Science 95: 2479-2488.
LAY, D.C. (Jr), FULTON, R.M., HESTER, P.Y., KARCHER, D.M., KJAER, J.B., MENCH, J.A., MULLENS, B.A., NEWBERRY, R.C., NICOL, C.J., O'SULLIVAN, N.P. and PORTER, R.E. (2011) Hen welfare in different housing systems. Poultry Science 90: 278-294.
MOINARD, C., STATHAM, P., HASKELL, M.J., MCCORQUODALE, C., JONES, R.B. and GREEN, P.R. (2004) Accuracy of laying hens in jumping upwards and downwards between perches in different light environments. Applied Animal Behaviour Science 85: 77-92.
NASR, M., MURRELL, J., WILKINS, L. and NICOL, C. (2012b) The effect of keel fractures on egg-production parameters, mobility and behaviour in individual laying hens. Animal Welfare 21: 127-135.
NASR, M.A., NICOL, C.J. and MURRELL, J.C. (2012a) Do laying hens with keel bone fractures experience pain? PLOS One 7.
NARS, M.A.F., MURRELL, J. and NICOL, C.J. (2013) The effect of keel fractures on egg production, feed and water consumption in individual laying hens. British Poultry Science 54 (2): 165-170.
PETRIK, M.T, GUERIN, M.T. and WIDOWSKI, T.M. (2015) On-farm comparison of keel fracture prevalence and other welfare indicators in conventional cage and floor-housed laying hens in Ontario, Canada. Poultry Science 94: 579-585.
POHLE, K. and CHENG, H. (2009) Comparative effects of furnished and battery cages on egg production and physiological parameters in White Leghorn hens. Poultry Science 88: 2042-2051.
RAO, S.V.R., RAJU, M.V.L.N, PANDA, A.K, SAHARAI, P.N., REDDY, M.R., SUNDER, G.S. and SHARMA, R.P. (2008) Effect of Surfeit Concentrations of Vitamin D3 on Performance, Bone Mineralisation and Mineral Retention in Commercial Broiler Chicks. The Journal of Poultry Science 45 (1): 25-30.
RIBER, A.B., CASEY-TROTT, T.M. and HERSKIN, M.S. (2018) The influence of keel bone damage on welfare of laying hens. Frontiers in Veterinary Science 5 (6): 1- 12.
RODENBURG, T.B., TUYTTENS, F.A., SONCK, B., DE REU, K., HERMAN, L. and ZOONS, J. (2005) Welfare, Health, and Hygiene of Laying Hens Housed in Furnished Cages and in Alternative Housing Systems. Journal of Applied Animal Welfare Science 8: 211-226.
SANDILANDS, V., MOINARD, C. and SPARKS, N.H.C. (2009) Providing laying hens with perches: fulfilling behavioural needs but causing injury? British Poultry Science 50 (4): 395-406.
SCHOLZ, B., KJAER, J.B. and SRADER, L. (2014) Analysis of landing behaviour of three layer lines on different perch designs. British Poultry Science 55: 419-426.
SHERWIN, C.M., RICHARDS, G.J. and NICOL, C.J. (2010) Comparison of the welfare of layer hens in 4 housing systems in the UK. British Poultry Science 51 (4): 488-499.
STRATMANN, A., FRÖHLICH, E.K.F., HARLANDER-MATAUSCHEK, A., SCHRADER, L., TOSCANO, M.J., WÜRBEL, H. and GEBHARDT-HENRICH, S.G. (2015a) Soft perches in an aviary system reduce incidence of keel bone damage in laying hens. PLoS ONE 10 (3): 1-14.
STRATMANN, A., FRÖHLICH, E.K.F., GEBHARDT-HENRICH, S.G., HARLANDER-MATAUSCHEK, A., WÜRBEL, H. and TOSCANO, M.J. (2015b) Modification of aviary design reduces incidences of falls, collisions and keel bone damage in laying hens. Applied Animal Behaviour Science 165: 112-123.
TACTACAN, G.B., GUENTER, W., LEWIS, N.J., RODRIGUEZ-LECOMPTE, J.C. and HOUSE, J.D. (2009) Performance and welfare of laying hens in conventional and enriched cages. Poultry Science 88: 698-707.
WEEKS, C.A., LAMBTON, S.L. and WILLIAMS, A.G. (2016) Implications for welfare, productivity and sustainability of the variation in reported levels of mortality for laying hen flocks kept in different housing systems: a meta-analysis of ten studies. PLoS ONE 11 (1):1-15.
WHITEHEAD, C.C. (2004) Overview of bone biology in the egg-laying-hen. Poultry Science 83: 193-199.
WHITEHEAD, C.C. and FLEMING, R.H. (2000) Osteoporosis in cage layers. Poultry Science 79: 1033-1041.
WILKINS, L.J., BROWN, S.N., ZIMMERMAN, P.H., LEEB, C. and NICOL, C.J. (2004) Investigation of palpation as a method for determining the prevalence of keel and furculum damage in laying hens. Veterinary Record 155: 547-549.
WILKINS, L.J., MCKINSTRY, J.L., AVERY, N.C., KNOWLES, T.G., BROWN, S.N., TARLTON, J. and NICOL, C.J. (2011) Influence of housing system and design on bone strength and keel bone fractures in laying hens. Veterinary Record 169: 414-414.
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World's Poultry Science Journal
  • ISSN: 0043-9339
  • EISSN: 1743-4777
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