Frustration: negatively valenced emotional state consecutive to the impossibility to obtain what is expected or needed. Frustration is very often triggered by restriction of natural behaviours thus resulting in thwarted motivation to perform these behaviours (EFSA Panel on Animal Health and Welfare (AHAW), 2022) 

EFSA Panel on Animal Health and Welfare (AHAW), Nielsen, S. S., Alvarez, J., Bicout, D. J., Calistri, P., Canali, E., Drewe, J. A., Garin-Bastuji, B., Gonzales Rojas, J. L., Gortázar Schmidt, C., Herskin, M., Miranda Chueca, M. Á., Michel, V., Padalino, B., Pasquali, P., Roberts, H. C., Spoolder, H., Stahl, K., Velarde, A., … Winckler, C. (2022). Methodological guidance for the development of animal welfare mandates in the context of the Farm to Fork Strategy. EFSA Journal, 20(7), e07403.