Plasma corticosterone levels in laying hens from three different housing systems: preliminary results

Adrenocortical and thyroidal hormones are physiological indicators of various forms of stress in the fowl. In order to establish possible variations in corticosterone levels, blood samples were collected from ISA Brown hens reared in three different housing systems (cage, floor and organic way). Results showed that corticosterone concentrations were highest in caged hens, intermediate in organic reared hens and lowest in floor reared hens. It could be assumed that in the last one system birds have an adequate space in controlled environment that permits them to satisfy, though partially, their behavioural needs without the presence of different chronic stress factors acting in the other systems.