Predatory animal poo and urine is very high in residual protein since the animal eats nothing else. Along with the animal's particular hormones in the manure, smaller animals are able to smell this, especially herbivores like rabbits and give the space a wide berth thinking that a dangerous predator is in the district and it's not worth dying for. Even composted, the specific smells linger on strongly.
Oddly enough, non-egg nor dairy vegetarians say they can smell the meat smells on the skins/sweat of non vegetarians. So if a vegatarian gives you the pinched nose look, it's probably because you stink to them. And please don't give me grief over this as I've been told this by several vegetarians.