"Old MacDonald Had a Farm" is a science fiction short story by American writer Mike Resnick, published in 2001.
The story is about a reporter who visits a farm where millions of genetically engineered animals are raised to help alleviate the world's food shortage. What he finds there is both brilliantly wonderful and tragically disturbing.
"Old MacDonald Had a Farm" was finalist for the 2002 Hugo Award for Best Short Story.