Citizen science - scientific research conducted with public participation - is increasingly being applied to animal welfare monitoring, extending the reach of welfare assessment dramatically.
Citizen science offers an extraordinary opportunity to extend animal welfare monitoring beyond what professional researchers and inspectors can achieve alone. The spatial and temporal coverage that thousands of engaged volunteers can provide is unmatched. In wildlife welfare, citizen science has already proven its value - detecting population changes, mapping disease spread, and documenting road mortality. For companion animals, owner-reported welfare data at scale could transform our understanding of common welfare problems. For farmed animals, trained community observers could supplement formal inspection regimes. The key welfare science challenge is ensuring data quality - structured protocols, clear definitions, and quality control mechanisms are essential to make citizen-generated data scientifically reliable.