One of my 3 week old Bantys feels like a feathered balloon. I notice him looking poofy the past couple days but it's been eating drinking and playing so I didn't think much of it but when I picked it up a moment ago it feels like he is completely filled with air. I was afraid I'd pop him and put him back down. What could this be and how do I fix it? I'm really worried he'll pop if it gets any worse.