Compacted (impacted) crop is an emergency. Food is not going through and stays in the crop. Chicken is hungry but the crop is full. There is a blockage somewhere in the track or chicken has eaten something like tough grass, straw or even carpet strands. Those bind in the crop. In this situation they go desperate and will eat anything. Make sure they can't get a hold of long hair which in combination with hard to digest strands of grass or straw will make a clump which cannot be digested no matter what chicken gets. Yes, hungry and desperate chicken will eat long human hair. Without surgery it is not curable and a visit to an avian vet is a must because the food that stays in the crop will sooner or later spoil and a bacterial or fungal infection will come. That is a death sentence. Pumping more stuff into the crop makes things worst. One of the causes of blockage can be parasite infestation like roundworms. They can completely block solids from going through. Liquids can still sip through (hence watery diarrhea). Deworming is a must. If you ever see even one roundworm in chicken poop it is an alarm and the whole flock should be dewormed before chickens get overwhelmed by these nasty parasites. I had dead roundworms in a pot with water for half a year(!) and they did not decompose. They are like indestructible strands of hard rubber.
Compacted crop is a secondary condition - something else is the primary reason that causes this condition. Regular deworming is a good way of preventing compacted crop.
Once you have a weak chicken with a big crop a visit to a vet is a must. Do not be cheap, you wanted chickens, and they depend on you.