The Poitou's coat is always dark brown or black. While lacking the stripes and cross-like markings on the coats of some other breeds of donkey, the Poitou should have a white underbelly, nose and rings around its eyes.
A purebred Poitou has a more massive bone structure and a larger foot than a part-bred animal, but the shaggy coat is such a dominant trait that even a 1/8th Poitou Donkey may resemble a pure-bred. In modern times, the Poitou's coat is still considered important but less so than size and measurements. Today, many Poitou Donkeys are shorn for the purpose of hygiene, but some Poitou are allowed to grow their coats out so as to be, in the French-borrowed parlance of their husbandry, "bourailloux".
The Poitou is also noted for its large body; the Andalucian ass is the only other European breed of donkey comparable size. Breeders selected animals with large ears, heads, and leg joints with the intention of breeding larger and stronger mules. Today the ears of some Poitou Donkeys are so large as to lay horizontal. A standard Poitou should stand between 1.35 m and 1.50 m at the withers and have a large, long head on a strong neck. Its withers should be unobtrusive and the back flat and long. The croup of the Poitou should be short and it should have rounded haunches. Its feet are bigger than those of other donkeys and are covered with the same long hair as its legs.
As with many ancient breeds, the origins of the Baudet de Poitou are somewhat obscure. The Roman Empire is said to have introduced the donkey and the practice of mule breeding to the Poitou region of France from which the Baudet de Poitou takes its name. Two breeds – the Poitou Donkey and a now very rare horse known as the "Mulassière" (mule breeder) – may have been developed side-by-side for the purpose of producing mules of superior quality. According to one source:
Baudet were kept purely for blood stock, not being good riding animals and great care was taken to ensure that the donkeys were not crossed or sold out of the region. As a result, the breed was kept pure for hundreds of years.
In the Middle Ages, owning a Poitou Donkey may have been a status symbol among the local French nobility. It is not known when the Poitou Donkey's distinctive characteristics were gained but they seem to have been well-developed by 1717 when an advisor to King Louis XV described:
There is found, in northern Poitou, donkeys which are as tall as large mules. They are almost completely covered in hair a half-foot long with legs and joints as large as a those of a carriage horse.
Up until shortly after World War II, the Poitou and the Mulassière were important in supplying mules to supplying France and elsewhere in Europe as their offspring they produced were reputed to be the "finest working mule in the world" and fetched a higher price. At the height of their popularity, the Poitou region produced up to 30,000 mules yearly. As mules and other draft animals were replaced with motor vehicles, there was less reason to breed Poitou Donkeys and their numbers swiftly declined.
In 2001, scientists in Australia successfully implanted a Poitou Donkey embryo created by artificial insemination in the womb of a standard mare. The procedure was done because the biological mother had joint problems and veterinarians were concerned that she might not be able to complete a pregnancy. A female foal was born strong and healthy and joined her parents as one of only three purebred Poitou in Australia.
La Maison du Baudet du Poitou at Tillauderie in Dampierre-sur-Boutonne, Charente-Maritime carries on the work of preserving and increasing the numbers of these unusual donkeys in France. In Vermont, another breeder pioneers the use of frozen semen. The success of breeding programs in France and the United States has allowed Poitou Donkeys to be sold to private owners.