Adorable puppy with a mouth so small she can't feed from her mother on course to be world's smallest dog Weighing in at just 163 grams, at five weeks old, little Angel may be the world's smallest puppy. Owner Kim Passero didn't think her Yorkie would make it. She calls her a 'little miracle', which is why she named her Angel. 'She's incredible, she has a personality and she is loving, she's like a typical dog, she's just really tiny.' Small, but perfectly formed: This little Yorkshire terrier puppy, born in a recent litter, might be a Guinness contender for world's smallest puppy When Angel was born, the odds were stacked against her. She was so small her brothers and sisters pushed her out of the way during feeding. And even when she was able to latch on to her mom, she couldn't get enough milk. Ms. Passero has been feeding her milk formula every two hours from an eye drop teat and now it seems she finally starting to put on weight. Angel was just one of a litter of seven puppies born at the start of September. Ms. Passero has her hands full, even if the dogs are only small. Lightweight: At 163 grams, the other puppies in the litter are around 400 grams, its mouth is too small to feed from its mother and has to be fed with a syringe or spoon She's up through the night to make sure all seven are eating and doing OK. The smallest dog in world is held by a Chihuahua named Milly. In order to qualify, a dog has to be a one-year-old. Guinness World Record measures a dog's height and length to make sure no one underfeeds their pets. Ms. Passero's home is decorated with Yorkshire terriers. There is a Yorkshire terrier welcome mat at the front door, and pictures of a beloved deceased Yorkie named Tinkerbell on the kitchen table. In her living room, an area has been fenced off where the regular sized puppies are snoozing. Breeding for a small size is controversial within the Yorkshire Terrier community, because of health concerns. Nursing: Angel's owner, Kim Passero, often has to say up all night to feed her littler of seven pups. She hopes to sell some for up to $1,500 but she says Angel will not be amongst them A document posted on the Yorkshire Terrier Club of America website notes the extra tiny dogs are 'extremely susceptible' to health problems. 'I'm sure there are people out there who are doing it for all the wrong reasons, for the money," she told The Star. 'We've done it from our heart, whatever happens, happens.' She says her smaller dogs don't have health issues. 'It's more people than it is, I feel, the dog. You have to really be careful because of their size, your job is to protect them. Passero says she is very selective about her customers - teacup dogs can sell for upwards of $1,500 - because smaller Yorkies need extra care. They can be stepped on, or sat on. She sometimes does home inspections before she agrees to sell. Angel will not be sold, she says. She needs to be protected forever, and of course, we have such a bond.