Wow, wouldn't that be a terrific resource, an encyclopedia of poop. Yeah..... I hope someone runs with this idea.
So, from what I have seen and read, I feel that dark metallic green (not the stuff we see after feeding peas or greens, no, I mean dark and metallic) poop is not a good thing. And sometimes dark, greasy runny poop can mean trouble.
Watery poo may mean they have been drinking alot, but somewhere I read that could be a sign of diarrhea.
I have one runner - I do not know which one - who has always had somewhat runny, dark brown poop. But everyone is healthy, we have had fecal tests done. There are always outliers, in my experience.
I was alarmed the morning I saw their poop color had changed from a tannish brown to almost black. Then I remembered we had our first outdoor day the day before. They had been eating soil.
The fact that they have throughput, in itself, is always a good thing and one of the first things many of us ask when a member worries about their duck's health.
A great idea! Had one the other day that I should have taken pictures of... his poop was bright green with yellow urates.