Lost a pet dog that ate a mouse killed when my sister set out a warfarin bait. It was gruesome. Please, please think very carefully when using poisons. Secondary affects are very common, and can be tragic.
Yes, everyone knows you don't tell sick people that enjoy poisoning animals where the poison is. But don't be a dick, do tell your normal neighbors (the vast majority unless you're extremely unlucky) so their pets aren't harmed or can receive prompt treatment.