Microchipping companion animals provides permanent identification that enables reunion after loss, and combining microchipping with updated registry information is a welfare intervention that prevents thousands of unnecessary euthanasias annually.
Microchipping is one of the clearest examples of a welfare intervention whose cost to the animal is trivially small and whose welfare benefit is potentially enormous. A lost, unchipped animal that cannot be identified faces shelter euthanasia after a short holding period — a preventable welfare harm that microchipping directly addresses. The brief discomfort of the implant procedure is immeasurably smaller than the welfare cost of euthanasia or prolonged shelter stress. Keeping registry information updated is a continuing owner responsibility that has no cost and maintains the welfare protection that the chip provides. Making microchipping universal and registries accurate is a high-leverage population-level welfare intervention.