This study compared egg quality parameters in layers under free-range system with prefabricated pens and backyard while emphasizing hen age. A total of 300 eggs collected from prefabricated pens and backyard farming families in the Çamardı District of Niğde Province were used as study materials. The assessed external and internal egg quality characteristics included egg weight, shape index, shell thickness, shell breaking strength, albumen index, Haugh unit, yolk index, and yolk colour. The effect of production system on albumen index, Haugh unit, and yolk colour score was found statistically significant. There was a significant effect of age on shape index, shell thickness, shell breaking strength, albumen index, Haugh Unit, yolk index, and yolk colour score. The effect of interaction between age and production system was statistically significant for shape index, shell thickness, yolk index, Haugh Unit, and yolk colour score. It was determined that the egg`s meat and blood spots percentages from the free-range and backyard systems were 10.6% and 15.3%, respectively. It was concluded that while eggs produced from free-range system are superior in terms of egg weight, shape index, and Haugh unit those obtained from backyard hens are higher in eggshell thickness, eggshell breaking strength, and egg yolk colour.
This paper reviews the effects of environmental enrichments in different laying hen production systems on hen welfare and egg quality. To improve hen welfare, several studies have investigated various environmental enrichments that suit different laying hen production systems. The positive results of these studies can enable such environmental enrichments to be utilized in commercial laying hen production. In this review, the most studied environmental enrichments in the free-range production system include forage, shelterbelt, and artificial shade in the outdoor area and novel objects and H-shaped perching structures in the indoor. These are associated with increased range use that positively affects hen welfare. In the aviary system, perches, and litter materials (e.g., straw, sand) as environmental enrichments are linked to improved behavioral expression, reduced stress, and enhanced immune system. Under the litter system, environmental enrichment with substrates (e.g., pecking stones, alfalfa blocks, silage, straw, barley) has been found to increase the foraging behavior of laying hens. This reduces severe feather pecking thus improving the plumage condition of hens. Although the effects of environmental enrichments on hen welfare have been assessed and scientifically proven in the reviewed studies, enough progress of their impact on egg quality traits has not been reported. The studies have shown that environmental enrichments have no significant effect on egg quality traits. On the other hand, appropriate pasture plants as environmental enrichments in the free-range production system in relation to hen welfare and egg quality have not been identified. Therefore, it is important to continue studies on environmental enrichments while emphasizing their influence on egg quality since it is a major performance trait in the egg industry. In addition, there is a need for studies to determine the ideal pasture species in the free-range production system that positively affects hen welfare and egg quality.
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.
Here, PRISMA guidelines were utilized to systematically evaluate the publications reporting the effect of thermal manipulation during embryogenesis on incubation performance, hatchability, and hatching quality of broiler chicks. The search and selection of eligible publications was through databases web of science, PubMed, and Scopus. Publications written in English between 2015 and September 2021 were considered. It is evidenced that during TM, key considerations include duration and strength of TM besides stage of embryonic development. The moderate elevation in incubation temperature (38.5–39.5°C) intermittently (3–18 h/d) between E07 and E18 improves the chick’s thermoregulation capacity and reduces any adverse effect of TM on hatchability, and chick quality (e.g., hatch weight and chick length) compared with continuous TM. In addition, high temperature TM (38.5–39.5°C) between E7 and E18 has no significant effect on embryo mortality, hatchability, and chick quality compared to standard incubation temperature (37.8°C). TM above 39.5°C significantly increases and decreases embryo mortality and hatchability, respectively compared with standard incubation temperature. In conclusion, the results of TM studies on embryogenesis, hatchability and hatching quality of broiler chicks are still contradicting, which is a possible limitation for its commercial use.
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