I'm posting this for a friend/neighbor. Here is her email reply when I asked her what their symptoms have been: The oldest which was a big rhode Island red we got it at the flea market and it was already grown, but we had it about 5 years. The 2 bannies that stay in the same cage that died were probably three years old. They really don't have any symptoms. Its like they are fine one day and the next we go out there and they are just laying there and won't get up or eat or drink and then they die the same day. Its not like they act sick for several days. That's what is so weird. Anyway, we cleaned their cage out and moved it to a new spot and cleaned their food and water bowls and I did put some apple cider vinegar in their water. We even have bought those liquid vitamins and put it in their water sometimes. Any way thanks for doing that. Any idea as to what may be going on?