Hen welfare in different housing systems

Abstract

Egg production systems have become subject to heightened levels of scrutiny. Multiple factors such as disease, skeletal and foot health, pest and parasite load, behavior, stress, affective states, nutrition, and genetics influence the level of welfare hens experience. Although the need to evaluate the influence of these factors on welfare is recognized, research is still in the early stages. We compared conventional cages, furnished cages, noncage systems, and outdoor systems. Specific attributes of each system are shown to affect welfare, and systems that have similar attributes are affected similarly. For instance, environments in which hens are exposed to litter and soil, such as noncage and outdoor systems, provide a greater opportunity for disease and parasites. The more complex the environment, the more difficult it is to clean, and the larger the group size, the more easily disease and parasites are able to spread. Environments such as conventional cages, which limit movement, can lead to osteoporosis, but environments that have increased complexity, such as noncage systems, expose hens to an increased incidence of bone fractures. More space allows for hens to perform a greater repertoire of behaviors, although some deleterious behaviors such as cannibalism and piling, which results in smothering, can occur in large groups. Less is understood about the stress that each system imposes on the hen, but it appears that each system has its unique challenges. Selective breeding for desired traits such as improved bone strength and decreased feather pecking and cannibalism may help to improve welfare. It appears that no single housing system is ideal from a hen welfare perspective. Although environmental complexity increases behavioral opportunities, it also introduces difficulties in terms of disease and pest control. In addition, environmental complexity can create opportunities for the hens to express behaviors that may be detrimental to their welfare. As a result, any attempt to evaluate the sustainability of a switch to an alternative housing system requires careful consideration of the merits and shortcomings of each housing system.

Welfare of organic laying hens kept at different indoor stocking densities in a multi-tier aviary system. II: live weight, health measures and perching

“…Others have reported mortality levels of 3% to 8% in multi-tier aviaries (Abrahamsson et al, 1998), but at higher stocking densities (17 hens/m 2 ) and without outdoor access. Most studies on mortality do not include multi-tier systems with outdoor access (Michel and Huonnic, 2004;Fossum et al, 2009;Lay et al, 2011). As a comparison, the median mortality in free-range and organic flocks in Denmark is 8% to 9% (E-kontrollen, 2013).…”

Current available strategies to mitigate greenhouse gas emissions in livestock systems: an animal welfare perspective

“…Osteoporosis is widespread in genetically selected commercial laying hens because of excessive loss of bone calcium that is repartitioned to egg shells (Webster, 2004;Whitehead, 2004). Osteoporosis increases the risk of fractured bones in caged birds when they are handled or when hens fall during flight (Lay et al, 2011). Moderate to strong genetic correlations have been estimated in pigs between rapid growth, litter size and feed conversion efficiency on the one hand and increased osteochondrosis and leg weakness on the other (Huang et al, 1995;Kadarmideen et al, 2004).…”

Free-Range Sistemi, Avantaj ve Dezavantajları

“… Açık alanda olunması ve sürü büyüklüğünün fazla olması nedeniyle hastalık ve parazitlerin yayılma riski fazladır [41].…”