Awesome!! The only thing I can think of is the potential for a raccoon to reach through that wire. I know it sounds unlikely, but I've lost a half-grown duckling through chain link (raccoon reached in and grabbed it by the head... it was gruesome so I won't go into further detail) and also a quail through 1/4" wire--the raccoon literally grabbed a toe and pulled an entire leg through and... again, gruesome. So I can definitely see a duckling going to sleep by that wire and...
No problem, though. The solution is either plexiglass or other solid material around the bottom three inches or so, or just a finer-gauge wire, again just around the bottom few inches. 1/4" wire is fine for ducklings--there's nothing on the duck small enough to be pulled through that size, so it's not like with quail. (With the quail, I solved the problem by putting a second layer of wire about four inches from the first, so the raccoon couldn't grab anything).
Oh, also--you might want to think about a way to lock it. I know I go on and on about raccoons, but I tell ya they are the world's worst predator (except bears, I suppose, which we thank goodness don't have here) in part because they are SMART. They can figure out how to open a latch. Latches need to be either physically difficult to manipulate (i.e., require strength, not just understanding, in order to operate) or actually locked with a key or combination. You can purchase these rings with a bar that clamps shut (wish I could remember what they're called) and they work well, because you have to have strong fingers to use them (my 7-year-old can do it, but just barely, and he often snaps his fingers in the process), and they're easy to install. Anyone know what they're called and can make this easier? lol
It looks really great, though, and SO much better than having ducklings in the house! I also have rabbit-hutch-like cages outdoors that I use. Mine do have wire bottoms, but I put a layer of straw over the bottom and it works great because the water falls through (not the poop though, alas), and I can just scrape the straw out and put in fresh to clean it. I just tuck the old straw up under the brooder and it catches the moisture and decomposes quietly over time. Of course, mine all have every single opening diminished to 1/4" or less, and the two-layer wire on the bottom to prevent reaching through from the bottom.
Good luck and enjoy!