I have 4 Zebra Finches, 2 males, 2 females. The males are going on 1 year, and I have no idea how old females are. They are all caged together and paired off long ago. For the past 3 1/2 days the one female constantly vocalizes - softly; slightly open mouth breathing although does not appear to be in distress - she is eating and sleeping (although still vocalizing) in her nest with her mate; bathing, etc. What might be wrong? Vent appears to be clear and droppings normal, but I'm nervous something is wrong. Help!