Figure 3.

The mean corticosterone concentrations (ng/g) of egg albumen from hens exposed to three rearing enrichment treatments (control, novelty, structural) sampled 4 days prior to and 7 days after the first range access. Box ends represent the first and third quartiles with whiskers extending to data within 1.5 x the interquartile range or upper and lower data points (excluding outliers) if the data do not reach the computed ranges. Isolated data points indicate outliers. The asterisk indicates that the structural hens significantly differed from the other treatment groups prior to the range access.