Young fowl can be identified by their smaller, softer features compared to old fowl. Young fowl have smooth skin and down feathers while old fowl have rough skin and visible feather follicles. Young fowl have a broad breast and small vent, while old fowl have a distended abdomen, hardened breast bone, and large extended vent. Poultry are inspected for signs of disease and aged based on physical characteristics to determine suitability for consumption.