The shelter's doors should come on last, otherwise they will just be in the way while building
. A connecting door, opening outwards from the shelter into the light is a must, regardless of any other entrances to the aviary itself. Separate doors to the external aviary and the shelter are not necessary. Remember to allow for a safety porch that allows you to enter the aviary without your precious birds escaping. It is best to have a door on the shelter, as this is where you will have the easiest access for the feeding of the birds.