Effect of Production Systems for Laying Hens on Hen Welfare

Özet

This review article discussed the effects of various production systems on the welfare of laying hens. The global egg production capacity has been increasing with the evolving production systems which are driven by the consumer preferences. In developed countries, the egg industry has shifted from focusing on quantity and quality of eggs to asking questions of how these eggs are produced. Animal welfare issues emphasized by consumers in these countries led to the banning of conventional cages as seen by European Union in 2012. Such legal measures have uplifted research in various alternative production systems which are thought to be animal friendly. Countries that have adjusted to alternative systems such as free range are registering an increase in the number of free range eggs which is a positive sign for an industry that is willing to adapt and move forward. However, in developing countries, conventional cages are still being used because they are fundamental to the quantity of egg production which is a success indicator of the egg industry. In addition, lack of awareness within the consumers and local producers that birds are sentient has not helped the poultry industry in such countries. However, the alternative production systems have also not fulfilled all the behavioural needs of the animals and, hen welfare issues such as keel and bone damage are common in enriched and perched systems. Also, the high prevalence of diseases and parasites are observed with significant levels in litter floor and outdoor systems an issue attributable to the direct contact between birds and soil or faces. Due to the continuing welfare issues in all laying hen production systems, it is suggested that in addition to genetic selection for traits like bone strength, reduced feather pecking, research should combine both the modification of equipment‘s or materials used in each production system and environmental factors such as illumination and temperature as an alternative to improve hen welfare.