Chicken has vent issues, could it be serious?

[bibzybean]

One of my chickens has seemed to have diarrhoea on and off ever since we got her 3 years ago. She has never had any other health issues and is fine in every other department. However for the past few months her diarrhoea has been constant, and her droppings basically look like half-digested grass in a pool of water. We regularly wash her, but have not yet taken her to a vet since our usual avian vet retired with not many good alternatives. Once again, she is physically good, is a heavy bird, and walks around/eats like normal, but drinks a lot. I am starting to get a bit worried as she has been slightly slower than usual, and it can't be good for her to have this problem for so long. Does anyone know what this could be, or how to treat it? Thank you

 

[azygous]

Could we have a photo of the poop to go along with your description of it?

And a full body photo of the hen so we can see posture and stance and eyes would help us gauge the state of her health.

 

[bibzybean]

Sorry for the late reply!

I have attached photos of the poop both fresh and dried. She is quite hard to photograph standing still but hopefully these will suffice. Her rear feathers are usually much dirtier but we cleaned and trimmed her recently so that she wouldn't get matted.

Here are her eyes and the standing photos. She looks a little wide in one of them but she doesn't stand like that too often:

 

[azygous]

She looks alert, not sick. The poop needs to be examined more closely, so could you repost and this time select "full size image"? That way we can zoom in and see more detail.