Skipper was born with six legs and two tails.
Previous research into dogs born with her condition suggests Skipper is the first to be born alive.
Skipper has congenital conjoining disorders called monocephalus dipygus and monocephalus rachipagus dibrachius tetrapus.
"You might notice she looks a little different - six legs!" Neel American Veterinary Hospital wrote in a Facebook post.
Skipper has one head and chest cavity, two pelvic regions, two lower urinary tracts, two reproductive systems, two tails and six legs among other things.
She also has early signs of spina bifida.
Despite her condition, Skipper has been able to move her legs but may need physical therapy once she is older.
Experts believe Skipper was born with this condition after fertilised egg tried to split into twins in the womb. However, the egg did not separate completely.
"Positively, her organs appear to be in great shape, she is peeing and pooping, and is very strong," her vets said.
"She nurses well and is growing appropriately so far.
"All of her legs move and respond to stimulus just like a normal puppy.
"It's possible she may need physical therapy and assistance with mobility as she gets older."
Skipper was among eight puppies, who are all healthy.
The post to social media from Skipper's vets stole the hearts of thousands of people, as the post has now gone viral with more than 2.5k comments.
"What a little cutie I hope you will stay on Facebook so we can keep up with this little one I would like to see how he does," one Facebook user wrote.
