Very small puppies and dogs can be prone to injury from pulling or tugging. Because harnesses disperse pressure over a larger area of the puppy's body rather than on their fragile necks, they are often a much safer choice. Harnesses offer more control over a puppy while they are learning to walk and behave on a leash. They allow you to stop your puppy from jumping on strangers without worrying about choking. Because there is no pressure on the neck, they are better for dogs such as Pugs and French Bulldogs prone to respiratory problems because they eliminate tracheal collapse associated with pulling. I recommend a back attaching almost solid material choke free harness for small breeds rather than one made with straps.  Small breeds as they’re more sensitive to pressure and the more solid design offers them greater comfort.