The odor is also a bit different than 'normal'. Sweet, but not nice to smell. Unpleasant enough to be 'off' but not like the sharp offensive odor of a normal fresh chicken poo. It is almost like vegetables/fruit that have started going bad and fermenting. Very hard to describe.
I must warn that in my experience and according to my vet, they don't always improve right away and may not seem to get better until the medication course is done or nearly done. Once she started improving, her droppings went back to normal, she ate well, and gained weight again.
Nambroth is right, the smell is so hard to describe. It's by no means stomach churning - it almost sweet, but at the same time not quite pleasant enough that you would want to go back and smell it again!
I had a girl who suffered from it as well, and it was thanks to Nambroth's experience with Coho and the information she posted that I managed to treat it myself. My local vet didn't have a clue about chickens (all he did was test her poo for worms even though it looked exactly like the photo in Nambroth's post!) so I decided it was 'kill or cure' and I treated her myself with amoxycilin - the only antibiotic I had available. It took a long time to see any changes, but I perserved through lack of any other ideas to try. However, once she started to show signs of improvement her recovery was pretty rapid.