Where does a farmer keep his really old cows? In a moo-seum.  

What do farmers use to make crop circles? A pro-tractor.

Why did they give the scarecrow a Nobel Prize? Because he was outstanding in his field.

What’s it called when a tractor waits for a pedestrian to cross the road? Crop yield.

Saw a sign a a farm that said, “Duck, eggs.” I was contemplating the use of the comma when it hit me.

Did you hear about the farmer with a wooden tractor? It had wooden wheels, a wooden engine, a wooden transmission, and it wooden work!