I have a 4 year old BQ hen who has been sitting on some dud eggs for the past few weeks to get the broodiness out of her system. I've noticed an odd sound coming from her when I hold her, it sounds like a quiet pop that you have to have her right up to your ear in order to hear it. Her energy, appetite, water intake, and typical cheerfulness seem to be normal, but it concerns me because I've never heard this from her before. No sneezing or discharge from her nares. It seems to occur when I massage her crop/chest area. Air in the crop? A joint popping? She has done prolonged stints at egg-sitting many times. Her bedding is a base layer of doggie pee pad topped with corn cob and 1.5" of aspen shavings.