I'm not entirely ignorant on the topic. Gastric acid is of too low a concentration (no more than 0.2M), and the time for which food stays in the stomach too short for very much reaction to occur. The acid first has to digest the surrounding food, unless we are to hypothesise that the consumer is going to eat lead pellets on their own deliberately. The surrounding meat is obviously largely made up of amino acids which are amphoteric and serve to partially neutralise the acid. This will have the effect of shortening the time of exposure and increasing the pH. Despite this countervailing factors, some lead / lead oxide will react with the acid, and the principal product is lead chloride. Lead chloride is only sparingly soluble in dilute hydrochloric acid and insoluble in water. This severely limits the possibility of the body absorbing a high dose. Once the stomach contents pass into the duodenum, the acid is neatralised, so the small amount of dissolved lead choloride will tend to precipitate out of solution again.
In the human digestive system, eating lead, while obviously best avoided is not that big a deal. It's not really helpful to confuse the effects of ingestion between humans and animals with radically different digestive systems - which are able to absorb high doses of lead. This is why I picked up on what appeared to be an explanation that while true for some avian species is really quite misleading for humans.
The risks of eating lead-contaminated food largely derive from preparing it with organic acids such as found in vinegar and fruits - this is why you shouldn't cook game in such recipes.
