Help!!

Hazel is a continental giant cross, female, 1year 3months old.
She has been eating normally (no diet changes apart from a couple of leaves of pak Choy??) she is still active.
A few months ago she lost a lot of weight (she was 6kg ish but now is around 4.5/5ish! ) and hasn't put it on since despite being fed extra pellets, hay and pieces of banana now and then. She had been to the vet and he cant find anything wrong with her...! I trust him he's a brilliant rabbit savvy vet.
She has been wormed, spayed, vaccinated.

She has dark, wet stools which are extremely 'squishy' and when she has accidentally stood on them they almost look like diarrhoea.
Her bum is slightly dirtier than normal but I still think she is capable of grooming herself.

I lost my first bunny to GI stasis and I'm so worried that it's going to happen again. I don't know if this is stasis though as she still eats normally and wees/poos but the poo is different to normal as said before.
Her bonded neutered friend is normal hasn't lost weight and still passes round golden poos.

I've tried putting probiotics in the water but she won't touch it if I do. I've also tried syringe feeding probiotics and critical care just to give her a boost, but I know this stressed her out and I try to avoid it as she still eats normally by herself.
Please help with what to do next?

Has the Vet run a full blood profile, especially looking at her Liver Function ? If not that is what I would be requesting ASAP.

Is she drinking more than usual ?

Has she become slightly less mobile, (which may account for her not keeping herself clean) ? Has the Vet considered whether she may have some spinal/hip pain-ie arthritis/spondylosis ? Giants are prone to both conditions, even when still at a relatively young age. Chronic pain from an arthritic condition can cause unexplained weightloss.

Another possibility is Hepatic Coccidiosis. This does not present in the same way as intestinal coccidiosis and symptoms can include weightloss/inability to gain weight, loss of over-all condition, dull fur and eventually a somewhat 'pot belly' and a pointy spine.

http://wildpro.twycrosszoo.org/S/00dis/Parasitic/Hepatic_coccidiosis_rabbits.htm

Giants are also more prone to heart disease. Initially this can present with unexplained weightloss moving on to other symptoms such as lethargy, poor exercise tolerance, increased respiratory rate and/or effort.

So as previously mentioned I'd request some diagnostics now if they have not already been done xx

Hi,

This sounds very similar to what happened with my little Arthur. Again, the vet couldn't find anything wrong with her.

I started feeding her some Pro-Fibre pellets which contained probiotics. They are the same brand as the Pro-Lapis probiotic sachets. At first she just ate around them but after a few days she gave in and ate them too. I also mixed probiotic powder with oats and water instead of offering it on it's own. She LOVED that! We got to the point where she loved it so much I was able to drop whatever medicines she needed in there and she would eat it all up. No stressful syringe feeding!
I read somewhere that oats are good for weight gain too but make sure there are no milk solids in them. Or if Hazel likes Banana, maybe mash the probiotic in with that?

This is just what worked for us though, I would definitely get the diagnostics mentioned above done.
We kept with this diet for about two years and she was a very happy bun!