The morning check that tells the story
The crop is a storage pouch at the base of a hen's neck where food waits before moving on to be ground and digested. In a healthy bird it bulges pleasantly full at roosting time and empties completely overnight, so at dawn it should feel flat and empty against the breast. That single check — feeling the crop first thing, before the hen eats — is how crop problems announce themselves. A crop that is still full in the morning, day after day, means food is not moving through, and the feel of it tells you which kind of problem you are likely dealing with.
What an impacted crop feels and looks like
An impacted crop is blocked, most often by a mass of long fibrous material — tough grass, straw, string-like weeds — that has balled together and cannot pass onward. The crop feels distinctly hard and solid, sometimes almost woody, or doughy and malleable like modelling clay, holding the shape of your fingers. The hen may keep eating and drinking because her appetite signal has not caught up, yet she gradually loses weight and condition because almost nothing is getting through. You may catch her stretching her neck, yawning or adjusting her crop with odd swallowing motions, and her droppings become scant and watery since so little food is passing. A sour, fermented smell on the breath means the trapped contents are fermenting, which worsens matters quickly.
What a pendulous crop looks like
A pendulous crop is a different failure: the muscles and skin supporting the crop have stretched, usually after repeated overfilling or an impaction that distended it, so the pouch hangs low and loose in front of the breast. It swings visibly as the hen walks, sits lower than it should, and feels soft and slack, often holding fluid and feed that slosh but never fully drain because the outlet now sits above the lowest point of the sagging pouch. These hens eat, sometimes greedily, yet stay thin — food ferments in the stagnant pouch instead of moving on — and they are prone to repeated sour episodes and slow starvation in plain sight of a full feeder.
What to do with what you find
A single morning with a slightly full crop after a day of gorging warrants a re-check the next dawn before worry; a crop that stays hard, doughy or pendulous across several mornings needs attention. Note which hen it is — in a flock, the bird quietly losing condition is easy to miss — and feel her keel for weight loss. A hen whose crop never empties, who is fading in condition, or whose breath smells sour should be seen by a vet rather than massaged and hoped over, because a complete blockage or a permanently stretched crop will not right itself, and the vet can judge whether the cause sits further down the digestive tract. Keep dated notes of morning crop feel and body condition for each hen in KinsLe's Pet Passport, so a slowly worsening pattern shows up in the record before it becomes a crisis.