My daughter has an 8 month old cockatiel named Remington. He is a hoot. He spends most of his day out of the cage and sings ALL. Day. Long! He has recently started what we call breaking rocks, lol. It isn't his usual nap time beak grinding. It's almost like he is chewing gum, only the gum is gravel, lol. He does it while stretching his wings (which made us freak out thinking he was cracking bones). Thankfully its clearly his mouth. He does it as he climbs my arm in between his chirp/talking. Is it a form of beak grinding? He isn't doing it when he is settling in for a nap, that's when he grinds. Thanks in advance!