Very good practice...
I think the Rabies vaccine is the only one required by law in the USA.
Rabies is required and can only be given by a vet in the USA because of it's zoonotic properties (infectious to humans). Giving the Rabies vaccine is no different than giving other vaccines, but care must be taken to not inject oneself or get stuck by the needle, and proper disposal/destruction of the needle, syringe, and vaccine container must be done as these also are a route of infection.
There are no 'specialty' singles for small dogs. All vaccines made for dogs are strong enough to vaccinate a dog weighing up to 100 pounds. This is where the problem of 'overvaccinate' originates, and why Dr Dodds recommends only one vaccine per vet visit and one month between vaccines for dogs.
Good breeders work closely with their own vets. My vet has a 'Breeder call List' to inform those who breed of any changes in practices, meds and/or recalls.
Quite a few breeders are trained by their vets to perform these procedures. These are minor procedures compared to whelping the pups at home.... Vets offices have many dogs and cats coming in on a daily basis, many of which are sick. To bring unvaccinated puppies into this environment is
always a risk, as viruses are airborne and can infect even if the vet's office is clean and immaculate. Even when the puppies are carried in, there is still a risk that the breeder could bring home something infectious on their clothes or shoes. Not only do they save money doing this.... they may also be saving the lives of their puppies.
IMHO, it is a big lump.
All human medicine and more is tested on Horseshoecrab blood before it ever goes into production.
Horseshoe Crabs - The Useful Horseshoe Crab
The Veterinary Profession is always looking to human medicine/procedures to find ways to better treat our pets.
The Vet ER I worked at 20 years ago had all kinds of equipment donated from local hospitals, from infant incubators for small critical patients, to EKG machines and Pulse Oximeters, Endoscopes, IV supplies and pumps, etc., which now is fairly commonplace (or should be) at many vet practices/clinics.
Stem Cell therapy is becoming an available treatment for our pets also. Funny though as it was first tested on animals before being used in human medicine, and now it's coming back to be utilized in the Vet Med field.
9/11 Search and Rescue Dog Receives Stem Cell Therapy at Va. Clinic Burke Vet Performs Stem Cell Therapy on Dogs with Hip, Knee Problems - Burke, VA Patch
To 'draw a line' between human and animal medicine would be severely limiting to both fields.
Also, when I worked at the human hospital, I remember hearing countless stories of nurses intervening in patients treatment, usually involved an error in medication or amounts in the charts.... takes a sharp nurse to catch and verify those kinds of errors.