The legs aren't separate, they are part of the single flat sheet that makes up one side (no joins, so nowhere for mites to hide; think about that every time you contemplate adding something somewhere). What do you want to do with the space? Ordinary size large fowl can fit under it to shelter if necessary, though I imagine a brahma would struggle…
Wow, I wish I had been able to determine that from their website, which is pretty uninformative when it comes to the deets like this (and dimensions.) I suppose that ship has sailed, though, since it’s integral to a side. The built platform top will be a sheet (no joins) of plywood with sealant.
Possible purposes of underneath are food and water, dust bath, or general unenclosed real estate.
…So I've found a Nestera in full sun stays surprisingly cool despite being black. But the nest boxes can get warm for a sitting hen, so I have either moved them to the shade of some trees in the height of summer or rigged up a shade sail over one if it's serving as broody coop in mid summer.
It does not get that cold here. You might want those vent covers on in mid winter. And plenty of shavings on the floor if you have floor roosters…
Ahh, this is very useful. We’ll hang on to the vent covers! I thought I had the shade part figured out, but the locations of pop door/ nesting boxes/ clean-out access nixed that, so back to pondering.
…Yes and they are worth every penny. They make daily poo-picking a doddle; just slide the tray out to clean, minimal effort and bending. And none has broken despite being made of a different (and much thinner) sort of plastic than the rest of the coop. Again, they have no joints to offer homes to parasites that will find and colonize your coop if they can.
It's far better than high roosts. None of my birds has ever had bumblefoot or any other ailment that can be caused by heavy landing from a too-high roost.
Ok, you’ve convinced me on the poop trays!

Do you set them over shavings? (Would there even be a point?) Do you fill the trays themselves with shavings? It seems like they would hop down into their droppings each morning, shavings or no, before I could clean.
As for the
joists roosts, this is their habitat, not mine, so I’m happy if they’re happy. Overall, they’ll be ~meter above ground level. I’m just used to seeing pics of high-up birds peering down at their human staff.
Thanks again! You’re the only poster I’ve found so far who admits to using (and liking) a Nestera, but I’ll attempt to cut down a bit on picking your brains into dust.