In most states if a child is over the age of 18, no the parents do not have to give an eviction notice. The parent can move the "adult child's" belongings out to the street if they want to. Living at home is considered a privilege after the age of 18. Now if a adult moves "back" in with a parent then an eviction notice is necessary. There are some loop holes here and there. As I said before, "in most states" it is not necessary.