I've had a few deaths lately with the same symptoms and can't figure out what it may be. I was hoping someone with more experience could help me out. It has always been weaned babies, up to 12 weeks old. The first thing I notice is the rabbit puts his head up in the air, pointing nose up and breathes hard. It appears that they aren't getting oxygen. The nasal area gets a blue tinge. From this time to death is very short-- just a few hours. I've never had more than one in a litter die this way. ~any ideas anyone?