The main objective of this project is to investigate whether cortisol in hair of pigs is a valuable biomarker for chronic stress. This forms the foundation for the future development of a biosensor which can be used on farms or in slaughter houses for a quick, easy and cheap way to determine cortisol in the hair of pigs. Hair (of pigs) as a matrix is easy and non-invasive to sample. Hence it is possible to evaluate animal welfare over an extended period of time in an objective, animal-friendly but also logistically and financially feasible way on a large scale.