UPDATE - in case it is useful for anyone else...
I took a urine sample & had it tested.
The results showed that the pig (male) had crystals in his urine which was making it difficult to get the urine out.
The vet said this was caused by feeding him the pig breeder rolls (ie commercial pig food) as this isnt suitable for Kunes and isnt suitable for anyone long term! Pigs bred for meat dont last long enough to develop a problem, but my pig is elderly and is a pet and is a Kune. Apparently the feed has too much protein for him and the magnesium content is high - which leads to crystals.
So, the advice was to take him off the feed, and replace with a mix of grass pellets (not too much), barley and/or oats, and sugar beet.
All feed must be soaked, as drieded feed (unsoaked) exacerbates the problem.
He also had a course of antibiotics, and a few days on Metacam for pain relief.
He is making a good recovery.
So, lesson is - avoid the commercial stuff, or at least dont feed too much of it. Always soak any dried food.
I hope that helps
