We have 2 females that have shared a cage for 3 years. They have always lived side by side ok, not going in for close contact but happy enough to be together. In the last few weeks Lily has started biting Daisy, we have been quite taken aback and concerned about them both really. It doesn't seem to be triggered by anything. They have a reasonable space in a C and C cage with various open ended hideys and floor time each day (although neither a very energetic!). Any ideas why and what to do to prevent this?