They may have heard the story but not realized the little red hen was a chicken. I currently know a woman, studying avian biology no less, who thinks ducks and geese are not birds. There is currently an animated cartoon on television the main character of which is a bull with a fully developed udder. So anything is possible. Personally, I would really like to meet the genius who drew the udder on that bull. There are several things to be seen on the underside of a bull, but an udder full of milk certainly is not one of them.
I think I know exactly what cartoon you are talking about and I cannot/will not watch it because it just bothers me SO much. I saw it before I was into the whole farm thing and I still knew it was wrong lol