15 January 2017 Last updated at 10:01 GMT
The lamb, nicknamed Skippy because "he looks like a kangaroo", was born on a farm at Chilton Foliat, near Ramsbury, Wiltshire, in 2016 and has to wear a specially-made fleece to keep him warm.
He has now started over-eating and is so round he cannot get up unaided if he falls over.
His owner, Sally Ann Fisher, has crafted a special bed for him in the back of a disused Land Rover.
A lamb born weak and thin without its own wool coat is now so podgy he has been placed on a special diet.