[northfifeduckling]

now this might seem sound funny to you all but I'll explain ...
our isolated mummy duck now always seems to look wet, after a bath and in rain it's really bad and lasts for a long time. She looks more like a wet dog than a duck! She did have only drinking water (deep enough to dip her head in) for 2 weeks so I wouldn't drown the duckling. Now she has her wee pool back for her wash. I take it her oil glands are not working well and I'm a bit concerned she might get too cold in this rubbish weather! Will all go back to normal? She'll have to stay in the isolated run until duckling has grown up a bit (another few weeks I guess)...

[goosepimple]

What kind of duck is she?  I always put a large plant saucer (well over a foot in diameter and about four inches deep) of water in with the mum and duckling - just put a few largish stones in that the ducklings can scramble onto.  They usually like a good preen after a bath and she's not getting the opportunity for a bath.  I empty/refill it 2-3 times a day.

[nic99]

This is something called wet feather. I have not seen it before in my ducks, but have read about it previously. Here is a link with some info about what may have caused it and how to treat it. Basically a problem with the oil gland as you thought.
 
http://www.majesticwaterfowl.org/artwetfeather2.htm

[northfifeduckling]

she does now have her wee bath back and has been using it for a few days. Duckling also had its first swims 
 thanks for the link!
I will definitely not try to catch the poor thing to give her a bath though, handling would just upset her (don't wanther to have  a heart attack), so hope it remedies itself now and waiting for good weather to help her dry off. 

[jaykay]

I bought a gander, who when he arrived, had wet feather.

It can happen because they haven't had any water to clean in, or in this case, he had been muddy and trying ot clean as best he could and used up all his oil.

He improved no end with plenty of clean water to wash in  but didn't totally sort out until he moulted and grew back new feathers.

I did nothing else but provide him with a clean beck and good food, and he is handsome and fine now 

Don't worry too much about her, it's not winter, it will sort out and they rarely get wet through to the skin even so.

[Beeducked]

As Jaykay says, lots of clean water and the ability to clean and preen should sort her out.