Duck Preening & Swimming Help

I'm a little worried about my Cayuga girl Topaz as she won’t swim or preen at all.

I have two of the plastic paddling pools with clean water each day as well as two buckets for head dunking and a washing up bowl in case they fancy a mini wash but she wont use any of them. None of the three new girls swim in the pools but the other two have good washes and preening sessions with the buckets and the washing up bowl splashing about but this little one doesn't.

She is very, very skitty and I tried to encourage her by bringing her in into a shallow bath yesterday morning but she got hysterical and in the end I took her back outside as she was so stressed out and her big Appleyard sister Amber got very protective of her and now wont let me near her  

I thought the girls might be reluctant to use the pools as the boys splash around in them (although the boys are gentle giants with them and have as of yet shown no interest in mating with them) so all day yesterday I brought the boys onto the patio and let the girls have the garden but still they showed no interest in the pools and she still wouldn’t wash or preen.

If you can help at all and give me any advice, as I really don’t want her suffering when it gets warmer - she needs to be splashing and playing like the others but just doesn’t.

Other than the water issue she is healthy - eats lots (I have them on a grain and pellet mix 30:70) and she does drink but not as much as the others do. They get greens and then also their favourite treat of tomatoes on a Sunday afternoon. The feed is next to water and they can either use the large feeder or a bowl that I put out for them that they seem to favour. I have given a cod liver oil supplement with some grain before bedtime and the water in the big water bottle has a supplement of acv for 5 days a month as they range with the chooks. There is also always grit etc available for them.

I have checked for nasties and there dont appear to be any and they were all wormed in January as well.

Any help to get her being a happy normal little duck would be greatly appreciated!

It's not that she wont now come near me now but Amber wont let me get near to Topaz - she keeps standing guard in front when I approach  In fact Amber is now standing guard in front of Jade as well and just tried to herd the boys away from me - she's a very good big protective sister duck and she obviously thinks I'm up to something bad and trying to hurt her little sisters!!!

Thank you Foxy 

She doesnt appear to have any wet feather although her underside is muddy mucky since she isnt cleaning herself properly.

I've just taken an old kitten litter tray out there with water in for her - hopefully she will get the idea!!! I'll take some bread out later and try to encourage her in (I better seperate the boys or they will be in there for bread!).

I'll move her and her sisters to the patio with the litter tray with water for a week so that I can increase their grain:pellet ratio for a little while although they are now between 16-24 weeks old with Topaz the youngest so not long until they will be laying I hope! With it being a mixed flock I cant up the ratio in the garden as the chooks will fill on grain (greedy madames!) and I'll not see sight of another egg for months  I'm sure the girls wont object to some patio time with extra grain - that is if Amber ever lets me near Topaz again!!!

I just watched out the window and it looks as if Amber is also trying to preen her now. Perhaps she is just the daft baby of the bunch