Laying hen strains and breeding system: A review of hen behavior and welfare, hen production performance and eggs quality traits in Africa and around the world

The breeding system for laying hens has been the focus of scientific research for many years. During the last decade, new laying hen systems were rapidly introduced with the aim of improving the health of poultry and the welfare of consumers, producers and industries on the one hand and meeting the requirements on the other hand. The choice of the genetic type usually depends on the production performance and the color of the eggs. To this end, the aim of this work was to make a comparative review of the results obtained by different authors on effect of strain and farming system on production performance (egg production and mortality) and the characteristics of egg quality (egg weight, proportion of different parts of the egg, Haugh units, egg yolk color and carotenoid) of laying hens. Although the productive performance in ground systems is often low compared to the cage farming system, the eggs of the ground-based system have been proven by many studies to have the best nutritional properties. This review of literature on the use of different strains and different table egg farming systems could give a new direction to research.