(Full disclosure: The author is an acquaintance of mine. I think he's a real cool dude.)
Gross, in the best sense of the word.
Sleeping Place of Feathered Swine is gross in a way that will still be intriguing to someone who has already grown bored of watching the poop beast of the vomit dimension spray its feculent gifts over the world. There is a creativity here that reaches beyond mere extremity, and may tickle the withered disgust reflex of even a seasoned grognard. It's the kind of thing that makes your players think "We cannot allow this to continue to live in the same world as us. We NEED to take care of it."
There are tons of things done right in this module. The art is very clean, evocative linework. The information conveyance is well considered, with a real effort being made at creating a table-friendly document. I'd like to seem more books used text of different sizes to help highlight more and less important passages. The quest is clever. You might call it simple or predictable, save for the dirty details of how the quest needs to be carried out. I imagine Mike Rowe would probably want to check this adventure out. The maps of each individual cavern accompanying its description were also appreciated.
On the con side of the ledger, there is an excessive amount of cavern description for many of the chambers. It never becomes too burdensome, but "It's a rock space that conforms to the shape of the map 2.5 inches south of this text" would have sufficed more often than not. There were a few times while reading that my eyes glazed over, & I read the same sentence over and over because the information was bland, and just not registering with me.
But none of these sections were very long. Perhaps a few lines or a paragraph at most before the text returns to more interesting fare. Which is true of pretty much everthing about the module. Every thought is kept short and digestible, which makes it a quick read and an easy module to run.
Overall, I'd say you ougt to toss the author a few bucks and give the module a read. This is a great little adventure. The sort you'll steal some ideas from, even if you never run it.