Is he usually a heavy drinker? (You know what I mean)
Is your heating on? Is he having more dry food/hay and less veg?
Is he losing weight? Weight loss + thirst are two signs of diabetes (in all creatures including people) Is his wee a normal guinea colour? Or has it got darker and smellier?
I noticed on a thread waaaaay back you were asking about salt blocks? If you do give them, take it out, they sometimes gnaw them because they are there, boredom/ busy rodent behaviour rather than needing salt.
Try and rule out all the contributary factors. If he needs a vet ,they'll ask for a fresh pee sample. Quite how you'd do that....
(my GP1 is a creature of habit. When he goes into his cage, he drops his bum to the newspaper and wees, copiously)
Your LittlePig is the 'marker' of the pair IIRC. Is he doing more marking than before? Something upset his territory?
I was wondering about this as I have a heavy drinking pig. Scruffy pig drinks a lot, but then he always has - think he's just a thirsty thing. Smooth pig, however, doesn't crack open the bottle until after lunch!
WRT to the sample - if you can get hold of a syringe (without the needle) P@H and The Range sell feeding syringes or they are available from Amazon.
If I cuddle the boars for 3-40 minutes they get dancey-stampy when they want to pee (we pop them in the paddling pool). If you put them on a hard or plastic surface, you can siphon it up and put it in a bottle that's been sterilsed with boiling water.
Or hold them over the toilet and flush the loo.That should make their bladders shift. Or is that just with children?