Guinea pigs are highly social prey animals whose welfare depends on conspecific companionship, appropriate diet, and living space far exceeding what small commercial cages provide.
Guinea pig welfare failures are extremely common due to widespread misinformation about their needs. Commercial cages are consistently too small. Single housing causes measurable stress. Incorrect diet leads to dental overgrowth and vitamin C deficiency causing scurvy. The Swiss requirement for social housing represents appropriate welfare policy that should be universal. Education before acquisition prevents most preventable welfare problems.