My little babypig Stewart (well, 8 months old, so not so much a baby any more!) has been making some strange noises in the past couple of days. They're not constant or even very frequent (not frequent enough to be while he's passing anything), but they are very strange. He's been a bit subdued, but I have thought that could be because he's been squabbling with his older friend and that he was a bit sad. But every night, maybe once or twice, I'll hear a disgruntled squeal. Usually it's when he's cleaning himself or eating a big bit of hay, but I don't know what's causing it. I've checked him over and he's got nothing outwardly worrying. Nails short, teeth in tact, no lumps, bumps or hair loss, no discomfort when I poke or prod. He's eating and drinking as normal, and seemed to perk up after a cuddle yesterday although he's still very subdued 
It's not much to go on, but does anyone have any suggestions?
It's not much to go on, but does anyone have any suggestions?