It does seem to be ceramic. At first I thought the "tray" part might be a lid to something that's missing, but the "tray" bottom looks like one, with markings and what have you barely visible under the glaze. It's definitely not a lid.
I'm wondering if there was ever a fourth trough, and if there's some sort of lid that goes over what's pictured above, or if what we see is what was gotten.
Whatever it is, it's some sort of novelty item that either never caught on or didn't last long. The weirdest thing about it is that it looks like it's been used. Whether that was for its intended purpose or something else, we won't ever never know.