It's not very likely such young chicks will have sour crop, but if the crops aren't emptying, I suppose it's possible.
Whatever time you go to bed, make it the last thing to remove their food and water. Then make it the first thing you do when waking in the morning to check each chick's crop to be sure they are flat and empty. Then give them their food and water immediately after.
Whatever time you go to bed, make it the last thing to remove their food and water. Then make it the first thing you do when waking in the morning to check each chick's crop to be sure they are flat and empty. Then give them their food and water immediately after.