Best flooring for goose pen?

[Sunny Side Up]

My Embden geese roam the yard all day long and are kept in a small pen overnight for their protection. It was fine when it was just Elmer & Gertrude, but now that it's being shared by their 7 growing children it is beginning to STINK!!!

We are in swampy South Florida where in the summer it is a gazillion degrees with 500 percent humidity. The pen is in a low end of the yard under an oak tree. Right now the floor is just the sticky dirt. All the poultry pens are in the back of the yard where the previous owners kept their horses, where they brought in some cheap fill dirt, which looks like a lot of chalky limestone stuff. After a very hard rain the yard floods, but it usually drains/evaporates by the next day.

Late next week will be the first opportunity I'll have to complete a new pen I've planned to house some of these geese. I hope that will help with some of the problem, to give them more floor space for pooping. Until then, what should I put on the floor of the existing pen to help with the smell & the sanitation?

I have some bags of play sand I could use, also some bags of decorative round river rock. Or I could rake up some pine straw. What would you advise?

 

[SunnybrookFarm]

Mine roam the yard. But I built a pallet house on a cement patio slab I had. I used straw oat straw when I had goslings and raked it out each day and hosed it off. I also started sprinkling Stall Dry on the cement before I added the straw. Due to our wet area.(WA state) I am installing a drainage area in my yard. Basically I'm digging down a little and then adding a little sand and then filling it in with gravel. I am also making paths for my kids to walk to and fro. Our water table is sooo high here and it was really muddy. So I am putting their wading pool and any waterers over it. I hope not to have any standing water this year. I also found out you need to rake the poop off the grass in the yard or it covers the yard in a stinky hard shell killing the grass. We just rake it into my raised bed and sprinkle ag. lime and add alayer of straw every once in a while. When I get too much we just shovel it into the compost pile. I would suggest a cement slab with something like a french drain around the edges.