it is not PDO's fetchAll() of course, but your query.
Which is not
IN (1007,1011,1012,1013,1014)
but
IN ('1007,1011,1012,1013,1014')
and of course it will find only first value as this string will be cast to the first number
One have to create a query with placeholders representing every array member, and then bind this array values for execution:
$ids = array(1,2,3);
$stm = $pdo->prepare("SELECT * FROM t WHERE id IN (?,?,?)");
$stm->execute($ids);
To make this query more flexible, it's better to create a string with ?s dynamically:
$ids = array(1,2,3);
$in = str_repeat('?,', count($arr) - 1) . '?';
$sql = "SELECT * FROM table WHERE column IN ($in)";
$stm = $db->prepare($sql);
$stm->execute($ids);
$data = $stm->fetchAll();