The newborn, named Billy, is around three times the size of normal lambs. Yet one of his siblings, born in the same litter, weighed only 4.4lbs.
Steve Booth delivered both animals, crossbred from a Charollais ewe and a Texel ram, at his farm in Upper Broughton, in the West Midlands.
He said: “It was a completely normal birth. We think this is the biggest one we’ve delivered and I’ve been doing this for 20 years now.
“We didn’t know it was going to be that big until I saw its head showing, it looked like an adult ram.
“The mother didn’t show any signs of having an extra large lamb inside her. The poor thing was stuck, his head and foot were popping out but his other foot was bent back inside his mother.”
After an hour of struggling, Mr Booth called his daughter Samantha and farm worker Helen Watchorn to help with the birth.
He said: “My hands are quite large and I couldn’t reach inside, so I had to quickly ring my daughter. She’s got smaller hands.
“She managed to push it back in to get the other leg. The lamb came out pretty easily, considering the size of him.”
He added: “Billy is now being reared on the bottle. He’s more like a dog – he follows you around because he’s expecting to be fed.
“He’s very bold, a little bit slower but very active. They have a different character to the smaller lambs.”
Ms Watchorn said: “He was massive – he’s definitely the biggest lamb I’ve ever seen. It was amazing.”