It just depends. The cleanliest animals I have are probably my geckos! I haven't seen them eating chicken poop, stepping in their own poop, pooping in their food/water, or killing and dragging up every animal in the countryside!
2nd place is the hedgehogs, 3rd the cats, 4th the chooks, and 5th - last place - my dog!
My chickens are cleaner by far!! They don't lick their butts
They don't scoot their butts on my carpets.
They don't eat chicken/cat and weird animal poo
They don't have nasty skin conditions that the vet can't figure out
And they don't have raunchy nasty stinky breath
The worst I get from my chickens is some poo on their feet once in a while (dog does that too) and the silkies get muddy when it rains (dog does too). I don't have the dust, I'm not sure why, but I've never had the same dust problems as others do
ETA: Then again, I do have to clean the waterer often of the baby chicks, dog doesn't do that.......
Ok, I just have to say this...
This other day my dog made a big poop in her kennel and, not to get too into it, but it was not a nice color or favorable texture if you know what I mean. So I took the kennel tray outside and hosed it off.
A couple hours later I let my chickens out to free range and to my surprise my naughty head-hen marched straight over to the left over mess in the grass and started eating it!!!! And of course, the other chickens saw she had a 'treat' and followed her lead. I chased them off.
So moral of the story is: MY chickens ate dog doo