It is a complex organ in which the digestive, urinary and reproductive systems converge. Hens therefore do not have a bladder.
The digestive system ends in the initial part of the cloaca (coprodeum), while the ureters instead open into the central part of the cloaca (urodeum). The section of the cloaca that precedes the anal opening and where feces and urine are accumulated is called the proctodeum.