We don't have a barn. The birds are in a detached garage. They get fed inside, but I leave the door open for them during the day to go back in to eat or drink.
I have a pair of geese that are traumatizing my ducks! They haven't gone in the fenced area - yet - but they are coming darn close. When the ducks are out, the geese will land on my barn roof (we found this strange for geese) and honk until the ducks are in a frenzy. They get a little closer...