Happy Chicken: A rich life worth living

The quality of life in animals is a growing concern but there is a lack of approaches to assess it. Methods for assessing cumulative lifetime experiences would provide objective means to study animals quality of life, including a range of aversive, neutral, and even rewarding events. Telomere dynamics (i.e. change in telomere length) might indicate the overall quality of an animals lifetime (i.e. cumulative) experience. Telomeres are repeating sequences of DNA at the end of chromosomes that shorten with each cell division. In humans, stressful experience results in shorter telomeres and stress-related telomere shortening can be mitigated and possibly even reversed by positive lifestyle interventions. Thus, telomere dynamics is a valid biomarker of cumulative experiences in humans. In line with human studies, research indicates shorter telomeres and accelerated telomere shortening due to negative life experiences also in non-human animals, but the interactive effects of positive and negative experiences on telomere dynamics in non-human animals remain unexplored. To validate telomere dynamics as an indicator of cumulative welfare in non-human animals we will measure telomere length in chickens as a model by manipulating the amount of positive and negative experience.