Any vet can administer shots it does not have to be Petco. You may want to request an appropriate dosage based on weight, because a lot of vets give the same dosage to a dog all dogs regardless of size which is dangerous to the small dog.

There is only one "dose" for the vaccines, regardless of the breed or size. Please speak with a veterinarian if you are concerned about your dogs vaccines.

I'm not familiar with dog vaccine dosages. You can Google the info. Years ago, you could purchase the vaccine at local rural pharmacies. The pharmacist was always a good source of info. You can also go to country farming & feed stores for vaccines for animals, not just for livestock.