There's a 1 story house where everything inside and outside of it was PURPLE. So what color were the stairs?

There were no stairs because it was a one story house!

It was a Sunday morning. Father was getting the mail, mother was in the kitchen cooking breakfast, little brother was playing Nintendo, big brother was playing the guitar, little sister was playing with dolls, and big sister was listening to music. Then everyone went into big sisters room and she was murdered! Who murdered her?

The father because it was a Sunday and no one gets mail on Sunday!

A rooster laid an egg on top of the barn roof. Which way did it roll?

It didn't roll - roosters don't lay eggs.