Yes, they are 2x6s, and there is a natural slope to help with rainfall drainage. We are building in our current coop/run location. The purpose for raising it and putting a floor in is to help prevent issues with mice/rats making their home under the coop and sneaking/chewing their way in.I'm in North Florida. You will never get cold enough, or deep enough in snow, for it to be a problem for your birds.
Can I ask why you are building a raised floor? and why you are framing with 2x4s for your floor if you are raising it??? (unless my eyes are playing tricks of scale and those are actually 2x6s). Since you are taliking about levelling it, can I assume you've looked at your ground, and already ensured rainfall (a problem we both share) will tend to move out and away from your coop and proposed run?