Hello. One of my boys, Patches, passed away on Sunday (two days ago). He was a year and a half, and had been to the vet a month ago, and was declared healthy. I went into the pig room, and noticed Bullseye (his brother) puffed up and not moving. Instantly worried, I leaned in to grab him, but he seemed in a daze. I followed his gaze and noticed two hind legs limp on the ground in a house. Instantly I moved the house and grabbed Patches. He was limp, and didn't move. It was my original thought that he was dead, as he was not breathing, but he was warm, and his belly was very soft, and upon palpating it, I couldn't feel any organs, just fat (he was not fat at all, around 900 grams). He twitched his legs, and made a weak high pitched coughing sound. I opened his mouth, but I felt nothing in his throat. By that point I was already in the car, heading to the emergency vet. About halfway there, he still wasn't breathing on his own, and he was starting to turn blue. I had been doing chest compressions, but he was no longer responsive to touch. I felt for a heartbeat, and he was gone. This is a guinea pig that was just declared healthy, still very young, and never had any health problems. Ever. Upon his necropsy, his GI tract had food in it, and liver, spleen, and lungs appeared normal. Today my normal vet is going to do a histopathy, and then we are going to bury him next to his father tonight. Does anyone have ideas?