We recommend using a soft puppy collar when your dog is very young before moving on to a wider and stronger leather collar. Puppies will inevitably scratch and pull at whatever collar you put on them, as they get used to wearing one.
The leather we use for our traditional dog collars in 1/2" - 1.5" widths is 3mm thick. Even with our thinnest 1/2" wide collars, as the circumference gets smaller the leather starts to feel more rigid. This could be uncomfortable for small dogs and puppies so we recommend using our leather puppy collar until your dog's neck circumference reaches approx. 22cm (8.5") and then moving up to one of our traditional leather dog collars. Depending on the breed, you may need a few collars for the growth period from puppy to reaching adult size.