The original poster said the chicken died of lead poisoning? How was that determined.?
excellent question. correlation/causation thing? 450mg per kilo of human to be lethal. seems logical an ounce or two would kill a chicken.
As far as lead being inert, once a bird ingests it their very acidic digestive juices go to work on it. There's a good reason lead shot is no longer legal in waterfowl areas. I use steel traps as well but still haven't found the best way to contain the splatter.
Where does lead come from?