Remodeling Duck Area...Ideas Please?

[Evadig]

I could not tolerate the mud anymore in the Muddy Run. I tore out the entire duck area, but now I need to rebuild.

• The soil is heavy clay.
• The roof leaks (it will be redone at some point, hopefully).
• The ducks have to stay in here for days sometimes due to weather or predators, so I want to have a pool.
• There needs to be room for a hallway.

Here's what it looks like right now.

This is what I was thinking about...

I could also do a wooden floor like I have already instead of the construction sand, so that I can just spray it off, but I would need to keep the water from seeping into the hallway and making that a mess.

Please let me know what y'all think! I need to get this done by the end of the week...