I'm not quite sure of your description and your definitions....incontinent means they cannot control their bowels. A prolapse is where rectal tissue is exposed...maybe this is what you mean? I have many good layers whose vents can be visualized through their feathers...which generally means they are currently laying. Anyone with a nice, neat butt with clean, full and fluffy feathers is normally NOT laying regularly.
How much of this vent can you see? Is it very red and moist, bulging out of the vent, or does it resemble a regular vent only looser and bigger?