Health Welfare of Laying Hens Reared in Cage and Non-Cage Systems

Authors

Keywords:

behavior, disease, feather pecking, footpad dermatitis, osteoporosis

Abstract

In this review, the welfare traits related to health status were revealed in laying hens reared in the cage and non-cage systems. In evaluating the health status of hens, infectious diseases, ectoparasites, production diseases, physical injuries, respiratory system diseases caused by air quality, and mortality were discussed. Each production system has specific traits that affect the welfare of the hens. Cage systems are more advantageous and hygienic systems in terms of viral and bacterial infections and ectoparasite transmissions than non-cage systems. However, restriction of movements in the cage disrupts the bone structure. It causes osteoporosis, especially in laying hens with high egg yield. Space limitation in cage systems is seen as a big handicap, especially for natural behaviors. The inability to exhibit natural behaviors causes a negative emotional state, contributing to the development of harmful behaviors such as feather pecking and cannibalism. In non-cage systems, footpad dermatitis, hock and breast burns are more common due to contact with the litter. Increasing environmental complexity in alternative production systems and unexpected conditions in the free-range area (predator attack, poor subsoil, too high platforms, etc.) cause increased bone fractures and injuries. Since there is no litter in the cage systems, the dust and ammonia concentrations are lower, and the respiratory system diseases are less than non-cage systems. Although deaths due to pecking and cannibalism are common in laying hens, the mortality can be kept at low levels with suitable management procedures.

In conclusion, infectious disease risks, contact dermatitis, physical injuries, respiratory system diseases, and low mortality in hens reared in the cage system are seen as advantageous in terms of health. However, on the other hand, restriction of natural behaviors makes it difficult for caged hens to maintain their metabolic and mental health.

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Published

2021-12-31

Issue

Section

Review Article