Chicks eat around the clock, so it's difficult to tell when the crop should go down, but it should decrease in size after a long period of sleep. Chick crumbles can feel like sand in the crop, and they can look pretty big in comparison with their size. In chicks only eating chick feed, not getting treats, and not on grass, they do not need chick grit, and the only thing that would impact their crop would be pine shavings or other bedding. Chicks raised on sand may ingest so much of it. He might just be the piggy of the group, but watcg=h him to see if it goes down a little between feedings. Or you can separate him for a few hours with only water, but keep him warm.
After wAtI've been watching him since noon Friday with no real reduction in crop size. He wants to eat, and I'm trying the egg and yogurt thing this am. He will definitely be kept warm! He did have an actual poop yesterday night and that was exciting since all he's been doing is peeing. I'll keep massaging it today and monitoring his intake. I just don't want to starve him or anything.
This might sound stupid but have you been wiping its bum? It seems like every now and then I have a needy one. It takes them longer on the whole poo thing. Warm rag wiping bum now and then seems to stimulate it. Sometimes if they are not pooing regular or are blocked up a bit they will hesitate on eating also. They do keep a pretty full crop though because they eat constantly. I have seem some sleep in the food bowl. Every little thing that wakes them up they eat again and then fall back to sleep in their food.