No, not if the bird keeps eating, it won't. Does it smell fermented or is it impacted? Some folks say sour crop when they mean impacted crop.
Same protocol or all sour crop issues. Separate the hen, 24 hours with no food, only water with 1/4 teaspoon of acidified copper sulfate (comes in powder form usually at the feed store) in a gallon in plastic waterer only. If you can't find that, use 2 tablespoons of organic, unfiltered apple cider vinegar in the plastic gallon waterer, changed daily. Day 2, add only plain yogurt. Day 3, add plain scrambled egg to the yogurt. Each day, massage the crop, several times each day, pushing toward the back of the crop, not upward. Day 3, maybe some soupy oatmeal added to the eggs and yogurt, but NO grains.