Confinement housing appears to be at the forefront of concern about laying hen welfare. This experiment examined the effects of floor space during rearing (315 or 945 cm2/bird) and adulthood (542 or 1648 cm2/bird) and access to a nest box on the welfare of caged laying hens. Measurements of the normality of biological functioning, such as plasma, egg albumen and yolk and fecal corticosterone concentrations, and heterophil to lymphocyte ratios, behavioral time budgets, mortality and efficiency of productivity, and measurement of hen preferences, such as choice behavior in Y maze tests, were used to assess hen welfare. There were no effects of treatment on physiological measurements. Hens given less space during adulthood spent less time mobile, inedible pecking, drinking, and preening and spent more time resting and feed pecking and sitting (P < 0.05). Hens with access to a nest box spent more time resting (P = 0.046) and less time sham dust bathing (P = 0.044) than hens without access to a nest box. There were no effects of space allowance on choice behavior for space or a nest box over food; however, hens with access to a nest box chose the nest box over food more than hens without access to a nest box (P = 0.0053).The present experiment provides no convincing evidence that either reducing space allowance in adulthood from 1648 to 542 cm2/bird or eliminating access a nest box results in disruption of biological function. Less space and no access to a nest box did not increase the choice for more space or a nest box, respectively, over food in the preference tests. However, reduced floor space reduced behavioral freedom and denying access to a nest box eliminated the opportunity for the motivated behavior of laying their eggs in a discrete enclosed nest box, both of which presumably provide hens with the opportunity for positive affective experiences.

Context Stress responses in chickens are commonly assessed from measurements of corticosterone in blood, but there is an increasing research effort to develop non-blood means of assessing the activity of the hypothalamo–pituitary (HPA) axis. It is common to measure corticosterone in the eggs and faeces. Aims We extended previous work by undertaking a study of caged laying hens comparing basal concentrations of corticosterone in plasma, faeces, egg albumen and egg yolk on a between-cage basis. We tested the hypothesis that there are positive relationships between corticosterone in plasma and corticosterone in each of the other matrices. Methods Blood samples were collected from each bird at a single point in time. In Experiment 1, these comparisons (between plasma concentrations of corticosterone on Day 1 and egg albumen, egg yolk and faecal concentrations of corticosterone on Days 1, 3 and 4 of the study) were made for hens of two ages under basal conditions, whereas, in Experiment 2, the comparisons (between plasma concentrations of corticosterone on Day 3 and egg albumen, egg yolk and faecal concentrations of corticosterone on Days 1 and 2 of the study) were made for hens housed at different space allowances with and without access to a nest box. The birds without a nest box had not had experience with a nest box prior to sampling. Key results There was a statistically significant (P = 0.012), but limited, positive relationship between plasma and egg albumen concentrations of corticosterone under basal conditions in Experiment 2. There were no other statistically significant (P > 0.05) relationships in either experiment. These results suggest that measures of corticosterone in the albumen, yolk and faeces of laying hens are unlikely to be robust predictors of basal concentrations of corticosterone in the blood. Conclusions Although there was some indication that concentrations of corticosterone in albumen may be related to concentrations in blood under basal conditions, based on all the results, this suggestion is made cautiously. Implications More comprehensive research is required to establish if measures of corticosterone in egg components and faeces are related to chronic basal activity of the hypothalamo–pituitary axis in laying hens. There is also a need to understand the impact of corticosterone on production, reproduction and welfare in hens from measures in both blood and non-blood matrices.