Welcome to the forums.
Have you been noticing this chick's crop emptying normally? When you gently palpate the crop, does it feel hard to the touch?
At this stage of development it should feel soft and squishy.
From the photo, I get the feeling something is not quite right with the chick and even though it's parent fed, it's possible that the chick has developed sour/slow crop and as a result the digestive process is put to a halt and the contents of the crop aren't emptying as they should.
Hens don't have the habit of overfeeding their chicks, to me it really seems the chick is having digestive problems.
You really need to see if this is the case or not.
If in fact the chick is not properly digesting the food and as result is also not pooping, you will need to seek urgent professional help from an avian vet specialist to hopefully assist the chick the best possible way. It's very important to keep this chick warm and hydrated, you may need to give it a tiny droplet of warm water on the beak with a little pipette or dropper.
You will also need to clean the nest box regularly as to prevent the chicks from getting poop on their faces, feet etc. This is also vital in terms of preventing bacteria build up. Hygiene protocols should be followed when raising chicks.
Be sure to update us on your chick. I'm wishing all the best for this chick and its siblings.