I didn't get around to suggesting these things, but I've always have in mind that some of these decorations should have been a sort of a power up. Since they take up space, they should have been of some use.

Examples:

• If you have a repaired windmill on your farm, then your energy recharge will be lesser. Say less 10 seconds or so.
• For chicken coop, then +1 eggs per harvest. Or maybe again lesser time of maturation.
• For milk tank, then +1 milk for cows and goats. Or again lesser time of maturation.
• If these were implemented, then more people will now be incentivized to put the decors in their farm.