Note that if you push the front panel on very tightly the chick's beak could get caught on the inside. You may need to pull it out a bit to make sure the head can freely move up and down.
I also designed the control knob so that it can be easily removed and replaced with a 1x1 plate, to 'hide' the mechanism. But, depending on the clutch power of your bricks, the 1x1 round bricks might slip. You can just replace the axle with a longer one that extends outside the egg to have a more solid control connection.