A man decides he wants to have a pig roast, so he goes out to a pig farm  to buy one. He agrees on a per pound price with the farmer and then  begins to select a pig. "How about that one?"

"OK," replies the farmer. The farmer then picks up the pig, puts it`s  tail in his mouth, lets it hang from his mouth and then declares, "This  one weighs 74 pounds."

"That`s amazing," the man says, "Are you sure you can tell a pigs` weight  by using that method?"

"Yep, says the farmer, we`ve used this method in our family for  generations." To prove his accuracy, the farmer puts the pig on a scale  and it weighs exactly 74 pounds.

"My son can do it, too," boasts the farmer. Sure enough, the farmer's son  comes over, puts another pigs` tail in his mouth, lets it hang and then  says, "This one weighs 83 pounds." The farmer then confirms his sons`  accuracy with the scale.

"My wife can do it, too," says the farmer. "Son, go get your mother."

The boy runs off to the house and returns a few minutes later. "Mom can`t  come out right now," says the son. "She`s busy weighing the mailman."