My bird has been acting very strange lately and I'm a bit confused why. Every day once or twice she will huddle into one of the corners of her cage with her tail in the air, and if I even look at her she will run at me and begin hissing and bobbing her head as if I'm a predator. I've had her for six years and shes never done this before. When she does it I make sure to give her personal space and talk softly, but she still acts so aggressively. I'm able to calm her down with some effort but she's really stubborn. I think she's going to lay an egg, but I'm not sure. Even as I'm typing this now she's hissing at nothing. Any thoughts on what this could be?