This paper reports on ethnographic research conducted in a behavioural epigenetics laboratory working on the transgenerational inheritance of "early-life stress" in rodents. The article describes the experimental steps that lead to the production of an understanding of "stress" as a nexus of molecules and experiences, biological and biographical events. In particular, the paper focuses on the experimental protocol of Environmental Enrichment (EE). EE is a housing regime for experimental animals that the lab employs to correct the "aberrant" epigenetic effects of "stress". The use of EE gets narrated as a therapeutic intervention restoring, within the experimental system of the lab, the centrality of the body as entity endlessly modified by the interactions with its (material and social) environments.Drawing from these observations, I detail the lab's mixed factual and value-laden work going into the production of a biosocial understanding of "stress". This process, I argue, oscillates between an emphasis on the material, organic and molecular traces of experiences and circumscribed attempts to deal with the biosocial complexities of this phenomenon in experimentation. As such, the practices reported here may be of interest to current STS engagements with post-genomics and the ways it forays into complex thinking of body-environment entanglements.