Reminds me of a story from Plimoth Plantation:

The re-enactment staff were stewing a chicken in a pot over an open fire. A man and woman, obviously the worst type of tourist and know-it-alls to boot, came by and asked, "What are you cooking?"

"A seagull," replied one of the cooks.

"Why, I didn't know they were edible! How can you tell when they're done?"

"When the feathers float to the top."