MATH PUZZLE: Can you replace...

A traveling salesman goes to a farm house. The farmer goes, I could put you up for one night, but youll have to stay in the barn. So he spends the night there and the next morning the farmer comes in, he goes, Were you comfortable? He goes, I had a great time; I talked to all the animals. He goes, You talked to the animals? He goes, Yeah I spoke to the chickens, they say you collect the eggs every morning exactly at five minutes after six. He goes, Thats exactly right. He says, The horse tells me his name is Otis, youve owned him for 10 years. He goes, Thats incredible. And he goes, I spoke to the cow, the cow says that her name is Elsie and you milk her every morning at exactly 8:30. And then I spoke to the sheep. And the farmer goes, Those sheep are lying.