UC Davis

In animal behavior studies, as in other fields, decisions about how data are collected directly affect the validity of the results and the interpretation of the findings. Thus, it is essential that the selected behavioral data collection strategy can accurately capture the behavior of interest. Within poultry science, a variety of behavioral observation sampling methods have been used. Although the method for determining the acceptability of a chosen sampling strategy should be provided, the reasoning behind the selection of a specific sampling strategy is seldom explained in publications. A previous study provided a framework for validating behavioral sampling schemes for adult laying hens. Rather than utilizing this framework, some researchers have used the results of the published sample validation to justify their sampling scheme. However, the results may not be generalizable due to sample size limitations. Application of previously validated sampling methods to new research contexts may be particularly problematic when a validation is completed on older birds but applied to other ages. This is due to developmentally relevant differences in activity levels and resource use. To emphasize the importance of sampling scheme validation and to investigate age effects on the sampling method, my thesis research examined the appropriateness of different interval scan sampling durations for estimating resource use by laying hen pullets reared in a single-platform aviary system. We predicted that resource use frequency changes as laying hen pullets age, and that different instantaneous scan intervals are needed to accurately capture platform/ramp, perch, and floor use at 6 and 12 weeks of age. The findings highlight the necessity of validating behavioral sampling schemes for each age and behavior independently, as well as reporting the validation process in research publications.