When Barney goes to the Flint farm alone, he sneaks into the barn through the man door which is part of the right-side door when the double doors are viewed from the outside. However, the next camera shot is viewing the double doors from inside the barn where we see Barney entering a man door in what would be the left double door when viewed from the outside. The man door suddenly switched sides as Barney stepped into the Barn.
When Barney is at the Flint farm sneaking from the barn to the hen house, we can see that the door to the hen house has a small window about head high on the outside of the door. However, when viewed from inside the hen house, the door has no such window. And when Flint swings open the door to bring in a sack, we can now see the outside of the door and see that there is no window in the door.