My
Little Monitor Coop has a plywood floor. I didn't put anything protective on it.
Since my management method and the generous ventilation keeps it absolutely dry there's no need. Some people use porch and floor paint. Some use Blackjack 57. Some use inexpensive sheet vinyl.
From my
article on Deep Bedding:
Deep Bedding: A dry, non-composting system where you keep adding bedding to the coop as it becomes soiled -- managing it by turning it as necessary (or getting the chickens to turn it for you) -- and clean it out only infrequently when the bedding has become both thoroughly soiled and piled up to the point of not being able to add more. Usually used above a floor in the coop but *can* be done in a covered run over dirt in a favorable climate.
Deep Litter: A moist (not wet, moist), system where the lower layers of material are actively composting while new, dry material is continually added to the top. *Can* be done on any floor surface but is most readily accomplished on a dirt floor because the dirt will seed the material with the beneficial composting organisms.
One of the most common management systems among BYC members is to use Deep Bedding inside the coop and Deep Litter in the run.
Why this height?
It provides very little in the way of ventilation or termite protection (common reasons for elevating a building off the ground), and isn't tall enough for the chickens to use the space and provides a near-ideal habitat for rodent pests.
I would advise that you either:
A. Raise it on legs high enough for the chickens to go underneath and keep the area pest-free (noting that you will want to have some kind of access for yourself since there will come a time that you need to retrieve a bird or an egg),
B. Make a full, concrete block foundation to sit it on -- bearing in mind the necessary depth to account for frost heave and skip the floor, or
C. Trench in a hardware cloth skirt all the way around to keep rats, snakes, and young chicks from getting underneath.