Insect farming is one of the fastest-growing sectors in alternative protein — producing millions of tonnes of protein annually from black soldier fly larvae, mealworms, and crickets. The welfare implications of farming hundreds of billions of insects are contested but increasingly taken seriously by welfare scientists.
The welfare case for insect farming reform depends on the probability of insect sentience. Current scientific position:
Given the uncertainty and the enormous numbers involved, some welfare researchers apply a precautionary approach — minimizing potential suffering even where evidence is uncertain.
Insect slaughter methods vary in welfare implication under the assumption of some sentience probability: cold stunning followed by shredding (considered more humane — cold reduces neural activity before killing); live grinding; hot water immersion (potentially the most painful method if insects are sentient); and desiccation (prolonged if insects are sentient). Welfare researchers recommend cold stunning as the standard approach pending better evidence on insect sentience.
Black soldier fly larvae (BSFL) are farmed at extremely high densities in composting substrate. BSFL are semi-social and naturally aggregate — their optimal density for conversion may be high. Crickets and mealworms are farmed at densities that exceed natural conditions, with uncertain welfare implications. Rearing temperature is a significant welfare variable — too hot or cold causes mortality and potential stress prior to death.
Even if the probability of meaningful insect sentience is low (say, 5%), the welfare expected value calculation changes when multiplied by hundreds of billions of individuals. Welfare scientists argue that even uncertain probabilities warrant attention when scale is so vast — a position that Rethink Priorities' research program on invertebrate sentience takes seriously.