Those are technically treats, & may cause dietary problems such as vitamin deficiencies, & fatty liver Disease if fed as the only diet.
He should be getting an All Flock, or Flock Raiser feed.
Doesn't it empty overnight? To know for sure is to check early in the morning before he eats, or drinks anything.
Coconut oil, & crop massage is often what does the trick. You massage the crop in a circular motion working stuff down the tube to the rest of digestive tract.
Just don't make him...
If no changes are seen in face color after a few weeks of treatment, it's possible that he may have something else like jaundice, which would indicate a liver problems. But he doesn't appear yellow, just pale.
That just looks like a normal chicken steadying itself on an arm that's not quite still. Pretty sure if he were on a solid object it'll show that he is actually perfectly fine balancing.