A farmer decides that his three sows should be bred, and contacts a
buddy down the road, who owns several boars. They agree on a stud fee, and
the farmer puts the sows in his pickup and takes them down the road to the
boars. He leaves them all day, and when he picks them up that night, asks
the man how he can tell if it "took" or not. The breeder replies that if,
the next morning, the sows were grazing on grass, they were pregnant, but if
they were rolling in the mud as usual, they probably weren't.
Comes the morn, the sows are rolling in the mud as usual, so the
farmer puts them in the truck and brings them back for a second full day of
frolic. This continues for a week, since each morning the sows are rolling
in the mud.
Around the sixth day, the farmer wakes up and tells his wife, "I
don't have the heart to look again. This is getting ridiculous. You check
today." With that, the wife peeks out the bedroom window and starts to laugh.
"What is it?" asks the farmer excitedly. "Are they grazing at last?"
"Nope." replies his wife. "Two of them are jumping up and down in
the back of your truck, and the other one is honking the horn!"