I have three male chins, all housed together. The calmest one has started kind of chirping at me if I'm eye-level with the shelf and talking to them. It's not an angry 'cack' or teeth chattering, but it's not quiet communication beeps either, like they do when they are playing. He doesn't seem to be distressed or in pain, but I've had my one chinchilla for several years and he's never made any noises like that. It's hard to tell what 'normal' is when they all have such varied personalities and habits! Has anyone experienced this or know what it means? Thanks!