A farmer decides that his 3 sows should be bred, and contacts his buddy down the road, who owns 3 male pigs. They agree on a stud fee, and the farmer puts the sows in his pickup and brings them down the road to the males. 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.
About the sixth day, the farmer wakes up and tells his wife, "I don't have the heart to look again. This is getting ridiculous, AND expensive. 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." says the wife. "Two of them are jumping up and down in the back of your truck, and the other one is honking the horn!"