
I would personally steer clear of "puppy parties"run by vets unless the person taking them is a dog trainer & not a vet(unless the vet is a DT as well)
We are happy for people to bring puppies to sit on knees or in a crate until the have had their jabs at our local DTC. I personally take my puppies out asap as I feel inless there is a local outbreak of a disease
My puppies are always pitched straight in with my older dogs, who obviously are out & about in the real world.
One of my dogs actually helped an older dog by him socializing with her & changing her from being iffy with other dogs to being a tart(literally)with all dogs. He gained by seeing other dogs than mine & accepting that they may not all want diving on etc
I'm working with a young dog that had been to a local vets PPs & its hard work when the puppy has been allowed to run riot & allowed to play with all the dogs in the PP. He has basically become a thug mugging everydog he sees instead of greeting them in a natural dog way