Two stories here, not directly about chickens, but certainly the ignorance of some:
1) Here is Cheyenne we have a very large rodeo / music festival every year. One year, my hubby was in the stands watching the rodeo and he overheard a man behind him tell his wife "See those little ones? Those are female bulls".
Um.... no, they are steers, castrated males. And this is where the steak you will eat for dinner comes from, too.
2) On a veggie gardening forum there once was a poster who kept asking, "is the stuff I grow safe if the cat once peed in the dirt" or "if there was old lead paint on a building two blocks away" or "if I used Roundup once near the garden". After two weeks of answering her questions, she finally admitted that her husband wanted a garden but she was just simply grossed out by anything that grew out of dirt.