Those movements of adjustments of the crop (when they have an issue going on) generally means a lot of yeasts are growing in the crop. Crops can itch. Sometimes you will even see the bird lift their right leg really high and scratch their crop from the outside.Did your crop go away? , my chickens neck is almost spinning she has something inside but cannot get it out will she on her own or should probiotics help?
Keep the bird vomited in the morning. This is very important to get all that gunk that has been sitting in the crop all night long out of the bird. The longer it sits, the more toxic it becomes, (it is rotting food), and grows more yeasts that get deeper into the birds body. Just remember to vomit them properly so you don't aspirate them...bird forward, and once the gunk starts to come out, count to 2 and then lean the bird back up. Give them a break and do this again until nothing else comes out. You will never get it all out of there.
Then keep the bird on a water soluble diet only, which means just layer feed or damp layer feed. I say damp because it becomes more interesting to eat and digests faster. No hard foods what so ever.
Keep probiotics in the water for a full week. Generally if this is a simple case of sour crop, this will clear it out of there in a weeks time. If it continues, you may need to add antifungal meds or go further to figure out why this bird continues to have a sour crop.