How do i get my aviary birds outside?

I have 2 zebra finches 2 atiels and 2 canaries, i have a 6 ft by 3ft Aviary will loads of perches and toys and food is always outside with water and a bath. we also have a shed part where we intended them to sleep in at night and to go in to shelter but only the finches and sometimes the cansrys go out. i really want them to come out. What should i do?!