In Don't Starve, does it hurt to leave rot on the ground? The wikia says that pigs will eat it, does it hurt them? Are there any actual negatives?
While I don't have an official source on this, I am currently on day 101 in my game, and I've had rot on the ground since day ~7. The only harm in leaving rot on the ground is that pigs can eat it.
That's not necessarily bad for the pigs, though it can be bad for you. I say bad for you because, well, rot is a pretty efficient fertilizer. Sure, it's not as good as manure, but it's useful in a pinch.
Ultimately, leaving your rot on the ground won't hurt anything, or anyone, so if you find yourself low on storage space, leave it lying around!