Abstract
I offer four ways to reinforce Birch’s precautionary principle so it can be used effectively and practically in deciding which animals to cover by legislation for humane treatment: (1) add one more credible indicator of sentience to the BAR rule; (2) use phylogenetic classification, not the outdated Linnaean classification, to test which animal clades have sentience; (3) disentangle the pain of suffering from sentience; and (4) reconsider the sentient status of decapods and insects to remove potential inconsistencies in the proposed framework.