Poitou Donkeys are huge, very shaggy and plain-coloured- I've never seen piebald ones and these are completely short-haired- I think there is a 2nd giant French breed of donkey- are these them?
Poitous (from France) are enormous and very shaggy. somehow your eyes can't accept their size as a Donkey is normally small and meek looking.. I believe in France they were used to cross with Horses to create enormous mules with great strength for ploughing/ agricultural work etc but mechanisation meant there was no demand and they became very rare. Possibly this American breed had a similar use.