That type of poo is typical when they are not eating for more than a day or two. Can you describe any other symptoms she has? Being ill will put them off of food, so like missnu01 said, it could be literally anything. We need more info.. as many details as you can.
Is she drinking (and how much)?
Does she seem interested in food but unable to eat, or does she just ignore everything? Have you tried different foods/treats?
Does she have any discharge around her eyes, nose, beak, or vent?
If you lean in close, can you hear if her breathing sounds clean, or if it sounds raspy or bubbly, gurgly or hoarse?
Can she move properly, walk normally, etc?
Does she seem alert, or very sleepy all the time, what is her behavior like?
Does her comb and or wattles seem either more pale, or darker, than normal?