Ethical dog breeding (Puppy mill worries)

We are looking into a breeder who is the closest within a 400-mile radius. After our initial conversation, the breeder indicated we would only be able to meet a dog after we paid for it and then not until the pick up. She provided some reasons, but it seemed like a red flag.

One reason she gave pertained to apparent guidance through her USDA license (APHIS) and the transmission of Parvo (can humans even transmit this disease to a dog?!).

She piqued my interest. In trying to locates this guidance, I looked up her license. In her most recent recertification, the inspection noted she had 30 adult dogs and 21 puppies. The inspection was dated September 2024.

Before placing any judgment, I’m wondering if anyone can help me understand if these are ethical practices that can result in a healthy and well adjusted dog?

Edited: spelling