call hog-fencing. It allows ventilation under the home, but keeps critters out. It's not something you can purchase pre-made, though, since it has to be sized to fit between the piers. It's typically constructed from 1x6 or 1x8 pressure treated boards that are set horizontally with a 1" gap between them
love the house style and picket fence
it's HUGE! patio up & downstairs... white picket fence! just flat out cute.