Jack was one of three lambs in a litter born at Adderley Wharf Farm near Market Drayton, Shropshire, UK. Triplets are rare and Jack was tiny, so owner Alison Sinstadt and her partner Simon Sherwin brought the Lleyn sheep into the house. They warmed him with a hair dryer and fed him milk.
Their nine year old springer spaniel Jessie herds the sheep on the farm, but took to Jessie as a companion. They sleep together in a dog basket in the porch. Jessie made a strong impression on Jack, who follows her around and tries to imitate her.
At six months old, Jack doesn't see himself as a sheep. He wears a collar and lead, fetches sticks, jumps on his hind legs, and makes a barking-like sound, somewhere between a baa and a woof.
When Jack is in the field with the rest of the sheep, he tries to herd them into a corner.
Alison said: "Jack doesn't even recognise sheep as his own kind because he tries to herd them up when he's in a field with them.
He even fetches sticks and jumps up on his hind legs like a dog. When we take Jessie for a walk on the lead Jack nuzzles me until I put him on a lead too."
"He is so sure he is a dog and we treat him like one. Jessie is a pet but she lives mostly outside. Jack follows her wherever she goes.
When Jessie comes in the house, Jack often comes in with him but we don't encourage it. The only thing which Jack does which is remotely sheep-like is eat grass. Apart from that he's just like a dog."