Kidney problems?

When my hen started to drink like mad I was concerned and I think you're right to be. She sounds an ill girl but she's young, has been having treatment so she might well be ok.  It could be kidney or sour crop, or something else entirely. It's not always easy to tell.  She might need bringing indoors for a bit to warm up.  If you're still concerned you could go back to your vet who might suggest further treatment or putting her to sleep.

I wouldn't delay seeking help as they can quickly go down hill

Don't feed her rubbish or stuff she shouldn't have. If she wants to be with her friends then let her.  You can keep an eye on her.  If she's disinterested and huddled up in a corner then you know all is not right.  If she's scratting for worms then you know she's feeling better.  Rice, pasta and sultanas are not hen food so I'd leave off with those.  Meal worms (dried from Wilko or the pet shop) are a good source of protein and she might take those from your hand. 
These are only a treat though but might encourage her to eat.  Have you got layer pellets for her?  I shall assume you have

I am not a hen expert but there are some hereabouts who can advise you better than I.

Hi Beano

What is happening to your hen sounds almost like a carbon copy of what happened to one of mine back in August. Ours had already stopped laying (she is about 2 1/2 and a hybrid).

The first thing she would do in the morning is drink loads of water, she refused pellets (not even that interested in pellet porridge) preferring to forage when outside the run for grass, bugs etc or if inside would peck at corn on the cob, or veg hung up as entertainment. Her droppings were the same as your hen's.

I took her to the vet and he thought she may have a kidney infection and also noticed that her droppings had a large number of flagelets (thgink I spelled that right!) which are tiny amoeba like creatures. I asked what could cause that & he seemed to think the eating of sweet things like fruit could but doing research online I saw that drinking water that has been standing for a while (puddles etc which all hens seem to prefer!) can also be a cause.

He gave her ABs but they didn't seem to be that effective (though they were in tablet form and I don't think I managed to get much down her). He then gave her a different liquid broad spectrum AB for a week along with OREGO-STIM which is an oregon based herbal additive for their drinking water (I mentioned this to somebody else in a post a couple of days ago). This claims, amongs other things, to dry up their poos and it certainly seemed to help.

One other symptom my hen had was the colour of the poos - a very green colour. This may have been to do with her eating more vegetation but I am not so sure as some of her droppings in the last week or so have been a similar colour though nothing like as runny, even though her diet is more balanced now as she is back on her pellets.

I am just keeping an eye on her now and giving them the supplement from time to time. My gut feeling is that it is a kidney infection which possibly hasn't quite cleared up, that seems to at least partly answer the excessive drinking of water that happened initially (this has stopped now and if anything both hens seem to be drinking less).

In between vets visits she seemed to manage to maintain her weight and seemed otherwise well. I partly put this down to the fact that after the first visit he told me to give them the max dose of avipro (another additive) in their drinking water so that she at least was getting some nutrients in her (it was OK for my other hen to have this too).

I don't know if my post is of any help but your case sounded so familiar to mine I thought it may help to share! Hope your hen recovers soon.
 

you could also try making her feed into a porridge by mixing it with hot water - many hens prefer this and it's a good way to get ill hens to eat their proper feed.
Avipro plus is a good idea when a hen is on antibiotics - it replenishes the gut bacteria that they lose. Hens have an intolerance to lactose so this is better than probiotics.
It might also be a good idea to ask your vet about worming your hens - assuming you haven't wormed them recently.

Since being on ABs for a suspected gut infection in June, one of my hens has not laid at all. She is under a year old but since the ABs, apart for the lack of eggs, seems to have been perfectly happy and healthy. But today I noticed that she was very quiet and has a very dirty bum. Her poo is white and watery. Tonight she is, unusually, not at all interested in the corn that the others are tucking into. Could it be kidneys?