A weird noise keeps coming from my ducks bodies. it sounds like ice or apples cracking. They don't seem to be making it on their own, so it's not a call or anything. Maybe it's coming from their feathers? I think they're too young to lay eggs, so I don't think they're egg bound. Are they hungry? I gave them a lot of greens and vegetables but the weird cracking noise is still there. Anyone know what this is??