IFAW is calling for new regulations on pet sales, and says an outdated Animal Welfare Act that doesn't address online sales has become a loophole for unscrupulous breeders to sell directly to consumers.
IFAW campaigns officer Tracy Coppola says investigators found thousands of "puppy-mill" ads promising to deliver any type of puppy, anywhere in the nation, and with no pre-screening of buyers.
"They are high-volume breeders who really are just looking for profit over welfare. So, no screening of potential owners means that they're willing to just send them to anyone - they don't care what happens to the dog - and they want to do it quickly."
Before the Internet, she says, most breeders placed ads and sold in their own region, and it was easier to visit their facilities and ask questions. Now, she says, 62 percent of the ads analyzed in the one-day blitz appeared to be from puppy mills.
IFAW says puppies from these high-volume operations can have health, genetic or socialization problems. Coppola says some of the ads appear to be from small, family breeders - when that isn't the case.
"Puppy mills know there's a close bond between people and dogs, and they prey upon that bond. That's one of the things that we really wanted to highlight with this investigation, that dogs really are members of the family. So, you wouldn't buy a member of your family online, obviously."
The U.S. Department of Agriculture has promised updates to the Animal Welfare Act, but they aren't final. Coppola says inspectors are shorthanded and underfunded, and that her group did the research to show how widespread the problem is - and to warn potential dog purchasers as well.
"I think the average person is quite appalled to even realize that this is such a huge market and that, because it's really not regulated, it's gone viral. Our investigation sheds a big light on that - and just looking at the sheer numbers, it's shocking."
IFAW recommends buying pets locally, and not online.