yawning

Our new cockatiel keeps opening her mouth wide and bobbing her head, any ideas why this could be? She also appears to be moulting and is scratching a bit and has a bald patch on top of her head, is this anything to worry about? Thank You!

please help me.... my cockarteil often looks like it is yawning. I am wondereing if perhaps that is not what it is doing. could it be poor air quality?