I have a shetland pony gelding that is about 8 years old. I have had him for 3 years and he has had no health issues of any kind. I got him for the grandkids and he pretty much just hangs around being a buddy most of the time, but also has a lot of spunk. He gets very light use but plenty of natural exercise in large pastures with hills. He has always been very healthy, and gets regular hoof trimming. Several days ago he suddenly seems like he is in some kind of pain. Not at all limping or favoring a foot, no usual sign of founder or navicular, definitely not colic, but just like he is stiff all over or is worn out. Just like I get some days with arthritis. His appetite is normal and his feed/pasture has not changed except of course that the grass is growing more right now. He gets no grain, only pasture and hay in the winter. But instead of the rambunctious normal pony he has always been, he now lays down a lot and moves very slowly with his head down. No signs of injury. I am stumped.