The first little pig built his house out of straw because it was the easiest thing to do.
The second little pig built his house out of sticks. This was a little bit stronger than a straw house.
The third little pig built his house out of bricks.
One night the big bad wolf, who dearly loved to eat fat little piggies, came along and saw the first little pig in his house of straw. He said "Let me in, Let me in, little pig or I'll huff and I'll puff and I'll blow your house in!"
"Not by the hair of my chinny chin chin", said the little pig.
But of course the wolf did blow the house in and ate the first little pig.