 Purchasers paid higher prices for Poitevin mules than for others, and up to 30,000 were bred annually in Poitou, with some estimates putting the number as high as 50,000.As mechanization increased around World War II, mules became outmoded, and population numbers for both mules and donkeys dropped dramatically.Poitou donkey and mule breeders were extremely protective of their breeding practices, some of which were "highly unusual and misguided."