I have three girls. They're healthy. The eat, run on their wheel, and are very playful. In September they lost a cage mate very quickly to a respiratory infection. The other three showed signs of illness but quickly recovered. Even with their health....every so often one of my girls starts to sneeze, and develops redness in the nose and eyes. It lasts for a day and then they return to normal. During their quick illness, they still eat, drink, and play. Is this normal? We've been beginning to chat about bringing in two boys (separate cage, but same air space). Is this a bad idea??