So the heavy breathing you are describing..how are you noticing this if his beak if close? Is his neck muscles going in and out deeply? Explain this more..what you're seeing.
His comb is the red spikey thing on top of his head.
The crop is on the right side of chest and should be a bit of ball shape at the end of the day (after eating all day). If he hasn't eaten and its a ball shape, then it could be impacted, but I would assess that after a night of sleep to make sure. First thing is the morning it should be flat.
Have you seen any of his stools (bowel movements)? Explain if it's runny, hard, color, etc. Look for worms as well.