Emerging research shows that chronic stress in animals alters their gut microbiome in welfare-relevant ways.
The gut microbiome is emerging as both a welfare indicator and a welfare mediator. Chronic stress — from overcrowding, social instability, or inadequate environmental conditions — disrupts the gut microbiome, increasing disease susceptibility and creating a feedback loop that compounds welfare problems. Early-life stress causes lasting microbiome alterations that affect animal health throughout their lives. This research creates new tools for welfare assessment — microbiome analysis can reveal cumulative stress exposure — and new interventions including probiotic supplementation.