A troll stops at a farmhouse to beg to spend the night. The farmer answers the door and says "Sure, we can put you up."
The troll washes up for dinner and meets the family downstairs. Sitting at the dinner table are the farmer, his wife, their son, and a gigantic pig who is sitting at the table like a human. Throughout the meal the troll tries not to stare at the pig, who sports three medals around his neck, as well as a wooden leg.
Finally, he can contain his curiosity no longer. The troll asks "Would you mind telling me about the bronze medal around your pig's neck?"
The farmer says "Sure. It's really an incredible story. Little Timmy here was swimming in the lake when he got a cramp and started to drown. This pig heard his cries for help, busted out of his pen, ran to the lake, and saved our son's life. So, we gave him the medal."
The troll is amazed and says "Well, how about that silver medal?"
The farmer says "A few months ago our house caught fire in the middle of the night while we were all sleeping. This pig saw the flames, busted out of his pen and ran into the house, waking us up in time. To show our gratitude we gave him that silver medal."
The troll says "While I'm at it, I might as well ask you about the gold medal."
The farmer says "My wife was attacked by a burglar several weeks ago. This pig heard her cries, busted out of his pen, and chased that man far away. To show my thanks I gave him that gold medal"
The troll sits in awe of the pig, who is blithely eating his meal with a knife and fork. He asks "What about the wooden leg?"
The farmer says, matter-of-factly, "Well, you don't eat a pig like THAT all at once!"