Tyler Allen-Day, 12, with giant donkey, Derrick. See SWNS story SWCAdonkey; A British sanctuary is home to this massive DONKEY which is set become the biggest - in the WORLD. The enormous young animal called Derrick is a staggering 16.3 Hands (5ft 7ins) tall - and is still growing. Whopping Derrick is an American Mammoth Jackstock - the largest breed in the world. The current record is held by Romulus in the Texas, USA, who measures 17 Hands - (5ft 8ins). Derrick is now just an inch short but his owners say he will easily become a world record holder for biggest donkey. The donkey lives at Radcliffe Donkey Sanctuary, Lincolnshire.